This is my “full surface” version of a “town heart” like the one by Karsten Blem.
The heart is difficult to weave, but not extremely. If weaving look at the picture to get the sequence right. Near the blades some weaving is omitted. You should line up the two parts after weaving each strip. And in no case you must use violence. If the parts will not line up you must identify the cause and sort it out. A pair of tweezers is a handy tool. You need two different parts.