Most astronomers think they are emitted by collapsed stars but that would not explain the repeating pattern.

An arpeggiator allows you to hold down a chord and set in motion a repeating pattern.

An aperiodic tiling uses a small set of tile shapes that can not form a repeating pattern.

The red letters were lit up for five seconds, followed by the floodlights for ten seconds, in a repeating pattern.

It incorporates a repeating pattern of circular forms to convey messages of centrality and inclusiveness.