Draw equal rectangles, 10 to 1 cicle, decrementing

Click on canvas to draw rectangles.

Cicle.    for( ; ; ) cicle.     Ten to one.

for(i=10 ; i >0; i--) {
    instructions
}

Effect: repeat 10 times the instructions

i     variable of the cicle
for   is a cicle with variable
i--        equivalent
i -= 1     equivalent
i = i - 1  equivalent

The cicle do the same as the incrementing cicle, only decrementing.