Sitting at the heart of your colony in Seed is the Kernel, the little structure that kicks off the founding of your settlement. And the earliest version of the Kernel looked very much like an actual seed, just large enough for two people to form the heart of the colony. The latest entry on the official development diary discusses how the design went from that earliest concept art to the current form, which is somewhat larger but still has that imagery of a seed planted on a distant world.
The design went through several iterations based on the same basic idea, including some versions that were fully mobile and others that specifically included terraforming agents on the kernel itself. Simple shapes and elegant designs were the rule through every iteration, though, but you don’t need to take our word for it; you can look back through the full course of the designs and see how the concept ultimately took form in the current version.