I need to know how I can combine these 4 for loops into one in program Processing - programming language - Java: int x = 0;
background(0);
size (900,500);

rect(400,0,100,100);

for(x = 0; x < 9; x = x + 1)
rect(100*x, 400, 100, 100);

for(x = 1; x < 8; x = x + 1)
rect(100*x, 300, 100, 100);

for(x = 2; x < 7; x = x + 1)
rect(100*x, 200, 100, 100);

for(x = 3; x < 6; x = x + 1)
rect(100*x, 100, 100, 100);