If you read further some commenters tried that and failed, along with setting straws into the jelly and nailing them and mixing solids into the jelly to improve the structural integrity. The results are only noted as mixed, so I assume they didn’t work out reliably.

I definitely have a few ideas: try smoother and surfaces to adhere to (does jelly suction to the surface?), set the jelly vertically in a box against the wall, try mixing cool whip into the jelly to thicken it…