How to use a three-fold cushion

How to use a three-fold cushion

The pictures illustrate how versatile a three-fold cushion is:

1. Folded up for storage
 
2. Folded as a one-fold seat
 
3. Extended

3. Extended but with the triangle still on top of the mattress – roughly equivalent to a two-fold cushion

 
4. Fully extended

for maximum length, when you really want to stretch out