<canvas width="350" height="300"></canvas>
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var pantalla=document.querySelector("canvas");
var pincel = pantalla.getContext("2d");
pincel.fillStyle = "darkgreen";
pincel.fillRect(0,0,350,300);
pincel.fillStyle = "black";
pincel.fillRect(50,50,90,90);
pincel.fillRect(210,50,90,90);
pincel.fillRect(140,140,70,100);
pincel.fillRect(100,190,40,110);
pincel.fillRect(210,190,40,110);
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