Fold in half diagonally both ways to create an "X" crease.
The "paper" thin line between safety and failure is the durability of the glass. A single drop from a height or a collision with a car results in the vessel shattering, leaving the fish to suffocate. The "Four Friends" Mechanic i-am-fish-v1-1-12-zip
If you were looking for a literal project (origami), you can follow these general steps found in common paper folding tutorials : Square Sheet: Start with a square piece of colorful paper. Fold in half diagonally both ways to create an "X" crease