This one is bit tricky since many edges are not parallel to any principal (x, y, z) axes.
The procedure is as follows:
Draw base lines a-b-c-d-e and f-g-h which are parallel to principal axes.
From top most edge, draw i - j (40mm). Join j – e
Parallelogram ijkl can be constructed easily as the edges are parallel to either xor zaxes.
Now we need to locate nand vwhich is achieved by first locating m and p
m lies 15mm below l, so just draw lmparallel to y-axes
Point p lies (also v) on the slope as seen in LHSV of the question. But vcannot be located directly.
To locate p, first draw kq parallel to je
q is any arbitrary point
Now from m draw line parallel to z axis. The point of intersection with kq is p
Now, v lies 15mm to the left of p.
Locate r 15mm below n (70-40-15 = 15)
Parallelogram rstu can be drawn as their edges are parallel to either x or z axis
Join s – t, t – g and u – h