I was really upset with Rotastak when we first purchased this cage, as there is no way the hamster could climb up the second part of the diagonal tube... the globe part is so deep there was no way our hamster could carry on up. However, now he uses his cage without problem, as we made him a little carpet to climb up. I just cut a strip out of a cotton tea towel (one with some texture)... long enough to line the tube from the top, down into the globe part.... and about 1 1/2 inches wide).. I then took the top part of the tube out of the upper cage, tucked the length of towel down the tube into the globe part (the end of the towel sits in the globe part and doesn't go all the way down to the bottom). I leave about 1/2 inch of towel hanging out of the tube at the top, and fold it over the edge of the tube.... so it basically lays flat on the part of the tube the hamster will walk up. I then squeeze the tube back into the hole of the cage, thus trapping the towel between the underside of the tube and the hole, so now it will not move when the hamster climbs. It does not matter if the towel does not lay completely flat, especially as it comes down the corner part of the tube, the hamster can still grip onto it, and use it like a rope to climb up. The towel can be washed when the cage is washed, it doesn't get dirty really, as it is used just for climbing up and down.... although our hamster has used it to cuddle up on, when we had the warm weather, the bottom end of the towel lined his globe perfectly. I hope this is not too confusing.... it really works.... our hamster's food is up on the top level, he is always up there. He does not use the other vertical tube, but we keep it in to join up the large bottom layer, to the top, otherwise the two cages slip and slide on each other. Hope this helps.