Can anyone elaborate about this joint? (triangular shelving)

[Josh Molaver]

Stumbled on this - thought it was pretty neat. Is this just routing a triangle into the shelf 'base', and a matching triangular shape into the supports? Or is there more to this technique?

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[Matt Day]

For just a little shelf I bet it’s just a triangular cut and glue.

[Jamie Buxton]

Yeah, I'm with Matt on this. It wouldn't be the greatest of joints -- the glue surfaces are all end grain on one face or the other. But for a small shelf built to sell, it'd be good enough.

I'd expect that the cut is not done with a router, but rather a table saw. In small production, the builder probably does the cuts with a cross-cut sled, with stops to ensure that the cuts meet at a point.