Isometric sketches

This task is about 3-D isometric drawings.
a)
Redraw the shape below on the isometric paper showing how it would look if an extra block was placed on each of the shaded surfaces.
 

 

 

 
 
 
b)
Complete the 3-dimensional drawing of the plan on the isometric paper below, as drawn by a person viewing it in the direction of the arrow.