An advanced teleportation system designed and used by Puppeteers, comprised of flat, open disks.
When one steps onto a transmitter disk, one is immediately transported at or near light speed to the next receiver disk. Molecular filters can be applied to the surface of the disk to transmit only certain substances. Most stepping disks are powered by an onboard nuclear fusion power generator. Manual reprogramming of disks is possible from a panel on the edge of the disk, usually in the form of switches that correspond to the local network of disks deployed in any given area. Stepping disks are deployed planet-wide over most of the worlds of Puppeteers, and were used extensively on the Ringworld by Baedeker and the protector Tunesmith.
Many safeguards are built into the functionality of stepping disks. If the transport surface of the disk is compromised or the space above the disk is too small to be safely used, the disk does not function.