<snapdata remixID="8928383"><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,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</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="149" y="149" heading="90" scale="1" volume="100" pan="0" rotation="1" 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="23" y="10"><block s="clear"></block></script><script x="86" y="227.99999999999977"><custom-block s="draw checkerboard %n"><l>8</l></custom-block></script><script x="113" y="158"><block s="gotoXY"><l>-171</l><l>-131</l></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;        break;&#xD;};&#xD;}&#xD;finally {&#xD;ide.savingPreferences = false;&#xD;};&#xD;</l></block><list><block var="which"/><block var="tf"/></list></block></script></block-definition><block-definition s="draw brick, length: %&apos;length&apos; width: %&apos;width&apos;" type="command" category="pen"><header></header><code></code><translations></translations><inputs><input type="%n"></input><input type="%n"></input></inputs><script><block s="setColor"><color>145,26,68,1</color></block><custom-block s="set flat line ends to %b"><block s="reportBoolean"><l><bool>true</bool></l></block></custom-block><block s="setSize"><block var="width"/></block><block s="down"></block><block s="forward"><block var="length"/></block><block s="up"></block></script></block-definition><block-definition s="set flat line ends to %&apos;flag&apos;" type="command" category="pen"><header></header><code></code><translations></translations><inputs><input type="%b"></input></inputs><script><custom-block s="set flag %s to %b"><l>Flat line ends</l><block var="flag"/></custom-block></script></block-definition><block-definition s="draw black square size %&apos;size&apos;" type="command" category="pen"><header></header><code></code><translations></translations><inputs><input type="%n"></input></inputs><script><block s="setColor"><color>8,5,0,1</color></block><custom-block s="set flat line ends to %b"><block s="reportBoolean"><l><bool>true</bool></l></block></custom-block><block s="setSize"><block var="size"/></block><block s="down"></block><block s="forward"><block var="size"/></block><block s="up"></block></script></block-definition><block-definition s="draw red square size %&apos;size&apos;" type="command" category="pen"><header></header><code></code><translations></translations><inputs><input type="%n"></input></inputs><script><block s="setColor"><color>255,47,31,1</color></block><custom-block s="set flat line ends to %b"><block s="reportBoolean"><l><bool>true</bool></l></block></custom-block><block s="setSize"><block var="size"/></block><block s="down"></block><block s="forward"><block var="size"/></block><block s="up"></block></script></block-definition><block-definition s="draw checkerboard %&apos;number&apos;" type="command" category="pen"><header></header><code></code><translations></translations><inputs><input type="%n"></input></inputs><script><block s="doDeclareVariables"><list><l>y-value</l><l>x-value</l></list></block><block s="doSetVar"><l>y-value</l><block s="yPosition"></block></block><block s="doSetVar"><l>x-value</l><block s="xPosition"></block></block><block s="doFor"><l>row</l><l>1</l><block var="number"/><script><block s="gotoXY"><block var="x-value"/><block var="y-value"/></block><block s="doIfElse"><block s="reportEquals"><block s="reportModulus"><block var="row"/><l>2</l></block><l>1</l></block><script><custom-block s="row a"></custom-block></script><script><custom-block s="row b"></custom-block></script></block><block s="doChangeVar"><l>y-value</l><l>40</l></block></script></block></script></block-definition><block-definition s="row a" type="command" category="pen"><header></header><code></code><translations></translations><inputs></inputs><script><block s="doRepeat"><l>4</l><script><custom-block s="draw red square size %n"><l>40</l></custom-block><custom-block s="draw black square size %n"><l>40</l></custom-block></script></block></script></block-definition><block-definition s="row b" type="command" category="pen"><header></header><code></code><translations></translations><inputs></inputs><script><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></block-definition></blocks><variables></variables></project><media name="U2L4-checkerboard_SV" app="Snap! 5.1, http://snap.berkeley.edu" version="1"></media></snapdata>