My kids love taking my couches apart and I'm forever having them put it back together. If I had my way I would buy a whole bunch of couch cushions because they play several games with them.
#1- They take the couch cushions and build houses. Then they hide in their little created spaces which makes their world seems smaller. They also get to lift and adjust the cushions as needed which helps other sensory issues not to mention the feel of the cushions.
#2 - They stack the cushions in a huge pile. We have 5 cushions downstairs and usually one or two regular pillows so all of these get stacked in a nice pile and then they climb up on them and sit. They love it and would much prefer to watch a movie this way rather than using any other seat.
#3 - They take the cushions and build tunnels to crawl through as they chase one another. This means a lot of up/down type motions.
#4 - They use the cushions as crash pads. Many times this includes seeing how far they can jump and make sure they land on the cushion they have in front of them.
#5 - They lay the cushions on the floor seperated from one another. Then they jump from cushion to cushion. They call this Bowser now from Super Mario Brothers when Mario faces Bowser in the castle with lava underneath them as they fight. Seeing it is lava they make sure they jump from cushion to cushion avoiding the floor at all costs. They make strange ways to jump from cushion to cushion and sometimes add a body pillow for a runway.
#6 - They use the cushions to make themselves into a sandwich.
These are some great alternatives for couch cushions if this is something you allow in your home or if your replacing your couch and can't figure out what to do with the other one.