Still baffled by the Tablet P's existence? Well, Sony's here to help! Earlier today, our brethren over at Engadget Chinese met up with Takeshi Goto, the head honcho of VAIO and mobile product producing, to learn how the Android clamshell went from several mockups (one of which was made out of a $4 wallet) right after the PDA era to the final product today. Between those two pivotal points on the timeline, Sony explored screen sizes between five to seven inches before settling on 5.5 due to hardware limitation; though the entire device ended up being about the same size as the 7-inch mockup. Later on, the manufacturer hooked up a couple of