@SimonCHulse these are two Hase Kettwiesel trikes. From the last one, the front wheel is removed and with some clever attachment the front of the trike is now attached to the rear of the other. This is standard for this trike. You can add as many trike as you want.

(Also #rule17, but that is another thing about #recumbents)

@meganL #regel17 is also for German people. The English translation would be #rule17.

And yes, there is a small idea that its good promotion of recumbent bikes to show photos. ;)

@moz @ascentale @scottsthoughts @bikenite

Also #rule17 or #regel17