Deep within the ruins, Tyler at last stood before the door to the central chamber. Only one task remained: finding a way in. He knew he would need to find the secret password to enter.

The door lock consisted of 64 octagons, each with a letter inscribed on it. Putting his fear aside, Tyler pressed one of the octagons. The 8 adjacent octagons lit up red but nothing else happened. He doubted the system would allow another wrong attempt.

Which octagon should he press to open the door?