I5 is a huge lego maniac. E8 is too, but he is a massive kit builder while I5 likes to modify the kits to make his own creations. Both of them can play with legos for hours on end and believe me when I say sometimes the floor is entirely constructed of them.
I5 got a Batman airplane set for his birthday which made a Bat plane and Joker's helicopter. I5 doesn't exactly care about producing the same ships more than once, but I just have to share his expertise in ship building and creating racing cars too. He used to the same thing with wooden train track...you'd build him one and he'd modify for hours.