Wikipedia
ShotCode is a circular barcode created by High Energy Magic of Cambridge University. It uses a dartboard-like circle, with a bullseye in the centre and datacircles surrounding it. The technology reads databits from these datacircles by measuring the angle and distance from the bullseye for each.
ShotCodes are designed to be read with a regular camera (including those found on mobile phones and webcams) without the need to purchase other specialised hardware. ShotCodes differ from matrix barcodes in that they do not store regular data - rather, they store a look up number consisting of 40 bits of data. This needs to link to a server that holds information regarding a mapped URL which the reading device can connect to in order to download said data.