A spawn area appears as small purple rectangular platform. The platform has a raised edge in the shape of a triangle on either side. In the center is a small blue raised platform which appears to look like a button. This may be what activates a spawn area when Rex209 walks over it.
Spawn areas act as checkpoints in Test Subject Complete. They will spawn Blue and Rex209 if they die in the level. They can be activated by walking over them. After being walked over, the spawn area will show a hologram of Rex209 above itself. Then, when Blue and Rex209 die, the parts of Rex209 will be transported to the spawn area and reassembled. Meanwhile, a voice will say "Reconstruction in process" in the background. After about two seconds, Blue will then be placed inside, and the player can once again move Rex209. Rex209 and Blue will be invincible for a few seconds after coming out of a spawn area.