An integrated view is generated for a model element being customized. The operational amplifier includes a non-inverting input terminal, an output terminal, and an inverting input terminal. Each flap may have a fixed end portion coupled to the diaper and a free end portion opposite the fixed end portion, which is not coupled to the reusable diaper. The slide block includes a second engaging hook for engaging the second engaging groove, and a press portion exposed through the through hole and pressible to enable the second engaging hook to disengage from the second engaging groove.