I have 12 stack n whack with shadows measure 20 inch unfinished. Sewing them 3 across and then maybe a nother border of lite then a thin drk to fame.
With the leftovers I have made some 4 patch posie`s to go after that. they are 7.5 unfinised. Should I cut down to 6.5?
What size sq assume they are cut in 4 do I cut for the triangles to put these on point to make into a block, and I
Thanks Gale

Gale, this is all a bit confusing, could you elaborate?

For square in a square units, the triangles that surround the square are half square triangles. You will need to cut two squares of 7". Cut each of these squares in half once. Now you have four triangles. These go on one 7.5" posie square block.

ok thanks.
will post picture when i get done
Gale

I'm sorry, I gave an answer and didn't really understand the question.

If I understood your question correctly:

The 7.5 unfinished squares - when set on point and framed - should finish to approximately 9.9 inches.

Are you planning to use the 4-patch posies with the large 20 inch blocks or are you planning to use them separately?

Thanks for all the work you went to.
I deceided to cut them to 6.5 so I cut triangles in 1/2 I cut 6 inch sq but having trouble going to see if I can find a viedeo.
Yes going to use them in the same quilt.
Gale
I meant to say 4 across like your picture.
So I just watched video and it said to have a 1/4 inch above point where I have more so better big than to small. Now how to sq them .I`ll play with my 12 1/2 sq and figure it out be fore I cut.

If your square will be CUT to 6.5 inches, then the square that you cut once diagonally should be cut to 5-1/8 - but I would cut it to 5-1/4 inches to allow for wiggle room

If you are going to cut the square into fourths - which I do not recommend, then your square should be 7-1/4 inch.

I am not following from 20 inch squares in your original post to talking about 12-1/2 inch squares in this one???

Anyway, hope what you are doing turns out well.

The 12 1/2 was my ruler I was trying to sq my block. Sorry not clear. Still ripping and still working on it.
Looks like an all dayer for me to get this lol
Gale