As the trapeze platform is the same height is the the same as the axis of the rope, for a situation where the floor is level, the length of the ropes needs to be less than the height of the platform. This is to avoid the acrobat face-planting at the lowest point of their swing. This means that the maximum distance between platforms, to avoid falling would need to be less than the height * 4. However if the floor is indeed level you can have any distance you like between platforms and any size you like of ropes and cross puzzle land on foot from the base one platform to another. That is assuming that the acrobat can walk that distance on level ground without falling over.