maybe kari is weird lol but I can use one grid high pens for her, and while she can easily clear it, she does not even try. she can clear are 3 foot pen anytime she wants to, it has no top, but she does not try, in over 1 year now she have only jumped her pen 3 times, and every time was to take her run, if she missed it for some reason or rather the night before. I guess I am just spoiled with a very well behaved bunny! lol kari has escaped the 1 grid high playpen before, but not by jumping it lol she just picked the lock on the door and opened it!