It's ok if the points extend beyond the frame. We want them long enough to ensure all points will meet. We can trim later if needed, but I found no trimming was needed at all when I finished.
lay the top right wedge on top meeting the center area and covering all underlying edges
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here's the whole block so far
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before adding the next wedge, lift the corners of the corner pieces up over the fillers like this where the pen is pointing. They need to overlap the fillers.
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