How it was built?

(1) Start with a template made from 1/8 masonite  (3) Bend, glue, and clamp the 1/4 inch strips of poplar. The strips are 1 1/2 wide. (5) Not shown - the sides are made up of 2 pieces of 1/4 inch insulation foam sandwiched between a piece  of formica on the inside and outside. This made it very bendable  and easy to insert into the groove in step 4.

(2) Build a bending form, using the sides as a guide. Drill 1 inch holes every 6 inches and insert 1 inch dowels - the rails will be bent around this dowels. (4) Bending from view from the top. Note the 2 strips that  are less wide then the other ones. This forms a perfect groove into which the side can be inserted later.