Start with Lisa as the common ancestor to the next computer and the original Mac. Next computer and the Mac gave rise to iOS Desk Mac and the iOS laptop Macs and all the versions at different price points. This may not be exactly like a living hierarchy but it shows that design creates a hierarchal structure. There is no common descent here and that plus not being built with a cellular structure can easily account for the difference in the hierarchal structure. Is it nested? That depends on definition.