1063. A Weekend on Earth B #12: A Facebook Find

Sameth on April 12, 2013

Not sure if that's obvious or not, but above the doorbell is a hand scanner.
And, of course, blue Erin would be able to go into brown Erin's home (without brown Erin having to be there) since their fingerprints are identical.

It's not so much that this is an Ambis invention. The dragons would've had their own, but the Ambis have a more high tech version that's more accurate and less glitchy than anything the humans or dragons could come up with at this point in time, so the Ambis implemented their handscanners onto the dragon's homes.