# by color name
fill orange
rect 10 10 50 50

# by hex val
fill #abcdef
rect 60 10 50 50

# by rgb where rgb stands for red green blue
fill rgb(255,255,0)
rect 110 10 50 50

# by rgba
fill rgba(255,0,255,0.3) where rgba stands for red green blue alpha or transparency
rect 140 30 50 50