Обратно к уроку "Maps"

Задача 8.

Consider the following maps $f$: {1,2,3,5}$\rightarrow${0,1,2}, $g$:{0,1,2}$\rightarrow${3,7,37,137}, $h$: {3, 7, 37, 137} $\rightarrow$ {1, 2, 3, 5} defined by the picture below.

Draw a picture for map a) $g\circ f$; b) $h\circ g$; c) $f\circ h\circ g$; d) $g\circ h\circ f$.