This one was a bit of work.
There are several versions of this pattern. The one I chose to focus on has an extra row of plain weave on R2. Other versions eliminate that row and expand the heart to the very edges of the square. It’s easy enough to create a Solid Heart by just filling the shape with U3s. Double Outline hearts can sometimes be a bit tricky. If I feel so inclined (or if someone requests it) I can work on Double Outlines for the other versions.
Corner Heart, Single Outline
Corner Heart, Double Outline
Corner Heart, Solid
Corner Heart, Single Outline (alternate) — this one eliminates the plain weave R2, but compromises the point at the base of the heart
Corner Heart 4, Single Outline, inverted
This sample shows an alternate pattern for R14 and R15 which I corrected on the diagram.
Corner Heart 4, Single Outline, inverted (shown in red)
For a Double Outline, combine the red and light green marks. (This version of the pattern has not been tested.)