<snapdata remixID="8923114"><project name="U2L4-checkerboard_SV" app="Snap! 5.1, http://snap.berkeley.edu" version="1"><notes></notes><thumbnail>data:image/png;base64,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</thumbnail><stage name="Stage" width="480" height="360" costume="0" color="255,255,255,1" tempo="60" threadsafe="false" volume="100" pan="0" lines="flat" ternary="true" codify="false" inheritance="false" sublistIDs="false" scheduled="false" id="1"><pentrails>data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAeAAAAFoCAYAAACPNyggAAAUO0lEQVR4Xu3VMWqbURSEUakIJKtwn/1vJE16ryKljbdwP+SBcNTP/+BouPN8+BEgQIAAAQLfLvD89hc9SIAAAQIECDwMsBIQIECAAIGBgAEeoHuSAAECBAgYYB0gQIAAAQIDAQM8QPckAQIECBAwwDpAgAABAgQGAgZ4gO5JAgQIECBggHWAAAECBAgMBAzwAN2TBAgQIEDAAOsAAQIECBAYCBjgAbonCRAgQICAAdYBAgQIECAwEDDAA3RPEiBAgAABA6wDBAgQIEBgIGCAB+ieJECAAAECBlgHCBAgQIDAQMAAD9A9SYAAAQIEDLAOECBAgACBgYABHqB7kgABAgQIGGAdIECAAAECAwEDPED3JAECBAgQMMA6QIAAAQIEBgIGeIDuSQIECBAgYIB1gAABAgQIDAQM8ADdkwQIECBAwADrAAECBAgQGAgY4AG6JwkQIECAgAHWAQIECBAgMBAwwAN0TxIgQIAAAQOsAwQIECBAYCBggAfoniRAgAABAgZYBwgQIECAwEDAAA/QPUmAAAECBAywDhAgQIAAgYGAAR6ge5IAAQIECBhgHSBAgAABAgMBAzxA9yQBAgQIEDDAOkCAAAECBAYCBniA7kkCBAgQIGCAdYAAAQIECAwEDPAA3ZMECBAgQMAA6wABAgQIEBgIGOABuicJECBAgIAB1gECBAgQIDAQMMADdE8SIECAAAEDrAMECBAgQGAgYIAH6J4kQIAAAQIGWAcIECBAgMBAwAAP0D1JgAABAgQMsA4QIECAAIGBgAEeoHuSAAECBAgYYB0gQIAAAQIDAQM8QPckAQIECBAwwDpAgAABAgQGAgZ4gO5JAgQIECBggHWAAAECBAgMBAzwAN2TBAgQIEDAAOsAAQIECBAYCBjgAbonCRAgQICAAdYBAgQIECAwEDDAA3RPEiBAgAABA6wDBAgQIEBgIGCAB+ieJECAAAECBlgHCBAgQIDAQMAAD9A9SYAAAQIEDLAOECBAgACBgYABHqB7kgABAgQIGGAdIECAAAECAwEDPED3JAECBAgQMMA6QIAAAQIEBgIGeIDuSQIECBAgYIB1gAABAgQIDAQM8ADdkwQIECBAwADrAAECBAgQGAgY4AG6JwkQIECAgAHWAQIECBAgMBAwwAN0TxIgQIAAAQOsAwQIECBAYCBggAfoniRAgAABAgZYBwgQIECAwEDAAA/QPUmAAAECBAywDhAgQIAAgYGAAR6ge5IAAQIECBhgHSBAgAABAgMBAzxA9yQBAgQIEDDAOkCAAAECBAYCBniA7kkCBAgQIGCAdYAAAQIECAwEDPAA3ZMECBAgQMAA6wABAgQIEBgIGOABuicJECBAgIAB1gECBAgQIDAQMMADdE8SIECAAAEDrAMECBAgQGAgYIAH6J4kQIAAAQIGWAcIECBAgMBAwAAP0D1JgAABAgQMsA4QIECAAIGBgAEeoHuSAAECBAgYYB0gQIAAAQIDAQM8QPckAQIECBAwwDpAgAABAgQGAgZ4gO5JAgQIECBggHWAAAECBAgMBAzwAN2TBAgQIEDAAOsAAQIECBAYCBjgAbonCRAgQICAAdYBAgQIECAwEDDAA3RPEiBAgAABA6wDBAgQIEBgIGCAB+ieJECAAAECBlgHCBAgQIDAQMAAD9A9SYAAAQIEDLAOECBAgACBgYABHqB7kgABAgQIGGAdIECAAAECAwEDPED3JAECBAgQMMA6QIAAAQIEBgIGeIDuSQIECBAgYIB1gAABAgQIDAQM8ADdkwQIECBAwADrAAECBAgQGAgY4AG6JwkQIECAgAHWAQIECBAgMBAwwAN0TxIgQIAAAQOsAwQIECBAYCBggAfoniRAgAABAgZYBwgQIECAwEDAAA/QPUmAAAECBAywDhAgQIAAgYGAAR6ge5IAAQIECBhgHSBAgAABAgMBAzxA9yQBAgQIEDDAOkCAAAECBAYCBniA7kkCBAgQIGCAdYAAAQIECAwEDPAA3ZMECBAgQMAA6wABAgQIEBgIGOABuicJECBAgIAB1gECBAgQIDAQMMADdE8SIECAAAEDrAMECBAgQGAgYIAH6J4kQIAAAQIGWAcIECBAgMBAwAAP0D1JgAABAgQMsA4QIECAAIGBgAEeoHuSAAECBAgYYB0gQIAAAQIDAQM8QPckAQIECBAwwDpAgAABAgQGAgZ4gO5JAgQIECBggHWAAAECBAgMBAzwAN2TBAgQIEDAAOsAAQIECBAYCBjgAbonCRAgQICAAdYBAgQIECAwEDDAA3RPEiBAgAABA6wDBAgQIEBgIGCAB+ieJECAAAECBlgHCBAgQIDAQMAAD9A9SYAAAQIEDLAOECBAgACBgYABHqB7kgABAgQIGGAdIECAAAECAwEDPED3JAECBAgQMMA6QIAAAQIEBgIGeIDuSQIECBAgYIB1gAABAgQIDAQM8ADdkwQIECBAwADHDvz88fiIn3hp/N/vt5d+v37819/3+omX5vk1Xn7/t9/zz7sNCX8xvID3FTXADdAA82sCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/Fpc2wK0DDiC/JtDS+tf8DHD0a3FpA9w64ADyawItrX/NzwBHvxaXNsCtAw4gvybQ0vrX/Axw9GtxaQPcOuAA8msCLa1/zc8AR78WlzbArQMOIL8m0NL61/wMcPRrcWkD3DrgAPJrAi2tf83PAEe/FpcmQIAAAQIELgLPS0iGAAECBAgQaAIGuPlJEyBAgACBk4ABPrEJESBAgACBJmCAm580AQIECBA4CRjgE5sQAQIECBBoAga4+UkTIECAAIGTgAE+sQkRIECAAIEmYICbnzQBAgQIEDgJGOATmxABAgQIEGgCBrj5SRMgQIAAgZOAAT6xCREgQIAAgSZggJufNAECBAgQOAkY4BObEAECBAgQaAIGuPlJEyBAgACBk4ABPrEJESBAgACBJmCAm580AQIECBA4CRjgE5sQAQIECBBoAga4+UkTIECAAIGTgAE+sQkRIECAAIEmYICbnzQBAgQIEDgJGOATmxABAgQIEGgCBrj5SRMgQIAAgZOAAT6xCREgQIAAgSZggJufNAECBAgQOAkY4BObEAECBAgQaAIGuPlJEyBAgACBk4ABPrEJESBAgACBJmCAm580AQIECBA4CRjgE5sQAQIECBBoAp9/jiHh9i9qJgAAAABJRU5ErkJggg==</pentrails><costumes><list struct="atomic" id="2"></list></costumes><sounds><list struct="atomic" id="3"></list></sounds><variables></variables><blocks></blocks><scripts></scripts><sprites><sprite name="Sprite" idx="1" x="160" y="-10" heading="90" scale="1" volume="100" pan="0" rotation="0" draggable="true" costume="0" color="255,47,31,1" pen="tip" id="8"><costumes><list struct="atomic" id="9"></list></costumes><sounds><list struct="atomic" id="10"></list></sounds><blocks></blocks><variables></variables><scripts><script x="391.000001" y="207.000001"><custom-block s="draw red square size %n"><l>40</l></custom-block></script><script x="375" y="166"><custom-block s="draw black square size %n"><l>40</l></custom-block></script><script x="81" y="21"><block s="receiveGo"></block></script><script x="146" y="78"><block s="clear"></block></script><script x="26" y="109"><block s="gotoXY"><l>-160</l><l>-130</l></block><block s="doRepeat"><l>4</l><script><custom-block s="draw black square size %n"><l>40</l></custom-block><custom-block s="draw red square size %n"><l>40</l></custom-block></script></block><block s="gotoXY"><l>-160</l><l>-90</l></block><block s="doRepeat"><l>4</l><script><custom-block s="draw black square size %n"><l>40</l></custom-block><custom-block s="draw red square size %n"><l>40</l></custom-block></script></block><block s="gotoXY"><l>-160</l><l>-50</l></block><block s="doRepeat"><l>4</l><script><custom-block s="draw black square size %n"><l>40</l></custom-block><custom-block s="draw red square size %n"><l>40</l></custom-block></script></block><block s="gotoXY"><l>-160</l><l>-10</l></block><block s="doRepeat"><l>4</l><script><custom-block s="draw black square size %n"><l>40</l></custom-block><custom-block s="draw red square size %n"><l>40</l></custom-block></script></block></script></scripts></sprite></sprites></stage><hidden></hidden><headers></headers><code></code><blocks><block-definition s="set flag %&apos;which&apos; to %&apos;tf&apos;" type="command" category="sensing"><header></header><code></code><translations></translations><inputs><input type="%s" readonly="true"><options>Presentation mode&#xD;Retina display support&#xD;Long form input dialog&#xD;Plain prototype labels&#xD;Input sliders&#xD;Execute on slider change&#xD;Clicking sound&#xD;Turbo mode&#xD;Flat design&#xD;Keyboard editing&#xD;Table support&#xD;Table lines&#xD;Visible stepping&#xD;Thread safe scripts&#xD;Prefer smooth animations&#xD;Flat line ends&#xD;Codification support&#xD;Inheritance support</options></input><input type="%b"></input></inputs><script><block s="doRun"><block s="reportJSFunction"><list><l>which</l><l>tf</l></list><l>var   stage = this.parentThatIsA(StageMorph),&#xD;        ide = stage.parentThatIsA(IDE_Morph),&#xD;        world = stage.parentThatIsA(WorldMorph);&#xD;&#xD;if (tf != !!tf) return;&#xD;&#xD;try{&#xD;ide.savingPreferences = false;&#xD;&#xD;switch (which) {&#xD;    case &apos;Presentation mode&apos;:&#xD;        if (tf != ide.isAppMode) ide.toggleAppMode();&#xD;        break;&#xD;    case &apos;Retina display support&apos;:&#xD;        if (tf != isRetinaEnabled()) ide.toggleRetina();&#xD;        break;&#xD;    case &apos;Long form input dialog&apos;:&#xD;        if (tf != InputSlotDialogMorph.prototype.isLaunchingExpanded)&#xD;            ide.toggleLongFormInputDialog();&#xD;        break;&#xD;    case &apos;Plain prototype labels&apos;:&#xD;        if (tf != BlockLabelPlaceHolderMorph.prototype.plainLabel)&#xD;            ide.togglePlainPrototypeLabels();&#xD;        break;&#xD;    case &apos;Input sliders&apos;:&#xD;        MorphicPreferences.useSliderForInput = tf;&#xD;        break;&#xD;    case &apos;Execute on slider change&apos;:&#xD;        ArgMorph.prototype.executeOnSliderEdit = tf;&#xD;        break;&#xD;    case &apos;Clicking sound&apos;:&#xD;        if (tf != !!BlockMorph.prototype.snapSound)&#xD;            BlockMorph.prototype.toggleSnapSound();&#xD;        break;&#xD;    case &apos;Turbo mode&apos;:&#xD;        if (tf != stage.isFastTracked)&#xD;            ide.toggleFastTracking();&#xD;        break;&#xD;    case &apos;Flat design&apos;:&#xD;        if (tf == MorphicPreferences.isFlat) break;&#xD;        if (tf)&#xD;            ide.flatDesign();&#xD;        else&#xD;            ide.defaultDesign();&#xD;        break;&#xD;    case &apos;Keyboard editing&apos;:&#xD;            ScriptsMorph.prototype.enableKeyboard = tf;&#xD;        break;&#xD;    case &apos;Table support&apos;:&#xD;            List.prototype.enableTables = tf;&#xD;        break;&#xD;    case &apos;Table lines&apos;:&#xD;                TableMorph.prototype.highContrast = tf;&#xD;        break;&#xD;    case &apos;Visible stepping&apos;:&#xD;        if (tf != Process.prototype.enableSingleStepping)&#xD;            ide.toggleSingleStepping();&#xD;        break;&#xD;    case &apos;Thread safe scripts&apos;:&#xD;        stage.isThreadSafe = tf;&#xD;        break;&#xD;    case &apos;Prefer smooth animations&apos;:&#xD;        if (tf != (StageMorph.prototype.frameRate &gt; 0))&#xD;            ide.toggleVariableFrameRate();&#xD;        break;&#xD;    case &apos;Flat line ends&apos;:&#xD;        SpriteMorph.prototype.useFlatLineEnds = tf;&#xD;        break;&#xD;    case &apos;Codification support&apos;:&#xD;        if (tf != StageMorph.prototype.enableCodeMapping) {&#xD;            StageMorph.prototype.enableCodeMapping = tf;&#xD;            ide.currentSprite.blocksCache.variables = null;&#xD;            ide.currentSprite.paletteCache.variables = null;&#xD;            ide.refreshPalette();&#xD;        }&#xD;        break;&#xD;    case &apos;Inheritance support&apos;:&#xD;        if (tf != StageMorph.prototype.enableInheritance) {&#xD;            StageMorph.prototype.enableInheritance = tf;&#xD;            ide.currentSprite.blocksCache.variables = null;&#xD;            ide.currentSprite.paletteCache.variables = null;&#xD;            ide.refreshPalette();&#xD;        }&#xD;        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