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size (100,100); //size of space
for (int x= -50; x < 100 ; x += 3){
ellipse (x,x-2,40,40);
}
//for the integer -50, the test is x is less than 100
//-50 plus 10 is -40)
//this ellipse will continue to run until x is greater than
//or equal to 100)