12 identical wedges repeat around the centre, across 5 concentric rings, giving 174 separate shapes to fill. At a relaxed pace that is roughly 131 minutes of colouring.
The pattern is built inside a heart rather than stamped onto one: the motifs bend to follow the silhouette, so every shape stays whole all the way to the point.
Lines are thin and the shapes small, which suits fine-tipped pens and adult colouring rather than crayons.
Every outline is a closed loop. On paper a broken line reads as a mistake rather than a boundary; colouring digitally, a fill tool escapes through any gap and floods the page.