NL-NWO 1981 Problem 4

A wire figure is held in different ways in a bundle of parallel light rays, so that different shadow figures are created in a plane perpendicular to the light rays. In this way one can form: (a) an isosceles triangle; (b) an isosceles triangle with altitude from the apex; (c) a rectangle containing an isosceles triangle; (d) a rhombus with one diagonal. The wire figure consists of eight straight pieces of iron wire, with each piece connected to both ends are attached to at least one other piece. Determine a figure corresponding to the above description is satisfactory, and indicate the direction of the light rays at which the shadow figures (a) to (d) arise.