The life simulator used is Golly which has a built-in script to generate these metapixel grids (select a pattern, and choose "metafier.py" from the scripts list).
The metacell uses a period 184 tractor beam, which acts as a clock. It pulls a block downwards by eight cells per impact, releasing a glider in the process. Some of the gliders are utilised; the rest are eaten. When the block reaches the base, it is restored at the top to begin the cycle again. Period 46 and 184 technologies (which are compatible) are used extensively throughout the configuration.
The rule is encoded in two columns, each of nine eaters, where one column corresponds to the 'Birth' rule and the other corresponds to 'Survival'. The nine eaters correspond to the nine different quantities of on cells (0 through 8). The presence or absence of the eater indicates whether the cell should be on in the next meta-generation. The state of the eater is read by the collision of two antiparallel LWSSes, which radiates two antiparallel gliders (not unlike an electron-positron reaction in a PET scanner). These gliders then collide into beehives, which are restored by a passing LWSS in Brice's elegant honeybit reaction. If the eater is present, the beehive would remain in its original state, thereby allowing the LWSS to pass unaffected; if the eater is absent, the beehive would be restored, consuming the LWSS in the process. Equivalently, the state of the eater is mapped onto the state of the LWSS.