*** To make a shape and duplicate them fastly without copy and paste.
First, make a square shape > select it > hold option > move to the right > then command D
(command + D only repeat the last action. In this case command D will repeat the movement)
*** If you have some squares (yellow fill with black stroke) and (black fill with yellow stroke) but you want to change the color of (black fill with yellow stroke) only, you can click one of them > click select > same > fill color
*** To make a pattern, make a shape > select all > click window > pattern option