Development is when you create models of the ass and the member purely for the sake of the trick, and you want them to just be combined forever. But immediately it turns out that for this they need support and propulsion devices, and thus, in turn, a source of energy and fuel. And even later it turns out that periodic repair is needed, because wear, ageing and all that, and you start to come up with how to make regeneration so that it is itself. By the way, you also turn the automatic search for fuel and refuelling. And you also have to take care that the fuel is also regenerative, otherwise it will not be enough for eternity. You have to create a almost eternal source of light, and self-replicating converters of light energy, which can be used as fuel, because the ass with the member initially did not intend to recharge with light, but to rework them already lazy. Then you face some in principle unresolved problem - the same aging, and you start to invent a bike, with the reproduction of the ass and penis, you have to wrap in the ass another hole, because the first is not suitable for this. In short, the result is a whole world in which members and asses hardly meet.
And it is always so, you think one thing, and something completely different comes out.