Place the bottom half of the shoebox on your work surface. Discard the lid. Designate one long side of the box as the front.
Cut the front of the box from top to bottom along the corners, creating a flap. Fold down.
Paint blue along the insides of the shoebox walls to represent sky. Glue green foam blocks along the floor of the box. Let dry, then spread glue on the blocks and sprinkle with turf shaker to create natural-looking ground growth.
Add plastic plants of distinctly different heights to simulate the levels of growth in the rainforest. Insert bottoms of fake plants directly into the foam for support. Add several bushes above the ground layer. Incorporate plenty of trees at the dense understory layer and the even denser, higher canopy layer. Include several much taller trees as the overstory or emergent layer.
Place fake animals in the layers where they might be found. Glue into place. Put monkeys or eagles in the highest layer, toucans or snakes in the canopy, leopards or jaguars in the understory and anteaters on the forest floor.