Similar to last week, but now you have to arrange the numbers 1-15 in a triangle such that each number is the difference of the two numbers immediately below it.

This time there is only one possible solution (plus its reflection), but even if you cleverly narrow down the possibilities with a couple of quick observations, there are still over 60000 triangles to check without a computer.

Alternatively, if I were to give you the bottom row, completing the grid will be trivially easy.

In an effort to find a sweet spot, I have given you the numbers on the left hand slope. Some more numbers can be placed straight away, whereas others you can only initially narrow it down to a couple of possibilities.