There are plenty of tutorials around for these homemade mushrooms, but I thought I would post just in case yet ANOTHER tutorial inspires someone to make one.
Mushroom circles are so great for straight arm support work, especially since your weight transfers from arm to arm while controlling the swings.
We did the usual thing and used an old electrical cable drum. There is a video link of my son doing circles on it below- always good to see that it works!
Not sure how these photos and video will upload, so if it doesn't work, tutorial and video can be found at http://www.thehousethatworkedout.com/homemade-pommel-trainer/