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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="170" y="130" heading="90" scale="1" volume="100" pan="0" rotation="1" draggable="true" costume="0" color="8,5,0,1" 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="83" y="224.8"><block s="doDeclareVariables"><list><l>Y</l><l>X</l></list></block><block s="doSetVar"><l>Y</l><block s="yPosition"></block></block><block s="doSetVar"><l>X</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"/><block var="Y"/></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="draw black square size %n"><l>25</l></custom-block></script><script><custom-block s="draw red square size %n"><l>25</l></custom-block></script></block><block s="doChangeVar"><l>Y</l><l>40</l></block></script></block></script><script x="327" y="169"><custom-block s="Draw Checkerboard"></custom-block></script><script x="90" y="137"><custom-block s="Draw Checkerboard"></custom-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 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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; 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