<snapdata remixID="8924760"><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="210" y="115" 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="198" y="147"><custom-block s="Make Checker Board"></custom-block></script></scripts></sprite><watcher var="y value" style="normal" x="10" y="10" color="243,118,29"/></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="Make Checker Board" type="command" category="motion"><header></header><code></code><translations></translations><inputs></inputs><script><block s="clear"></block><block s="gotoXY"><l>-190</l><l>-125</l></block><block s="doRepeat"><l>5</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>-190</l><l>-85</l></block><block s="doRepeat"><l>5</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><block s="gotoXY"><l>-190</l><l>-45</l></block><block s="doRepeat"><l>5</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>-190</l><l>-5</l></block><block s="doRepeat"><l>5</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><block s="gotoXY"><l>-190</l><l>35</l></block><block s="doRepeat"><l>5</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>-190</l><l>75</l></block><block s="doRepeat"><l>5</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><block s="gotoXY"><l>-190</l><l>115</l></block><block s="doRepeat"><l>5</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><variable name="y value"><l>20</l></variable></variables></project><media name="U2L4-checkerboard_SV" app="Snap! 5.1, http://snap.berkeley.edu" version="1"></media></snapdata>