Rectangular strings

I've been playing in the string bin again recently,

turning out rectangular blocks that finish at 6 by 9 inches

When they go together they make large diamonds.

I have a few rules for these instead of going entirely scrappy.

I'm using brights on the inside diamonds, and darks on the outside.

I've got lots of variety going here to give it more energy

and I'm trying to stay away from muddy colours on both sides.

This is my technique: I cut 6 by 9 inch foundations from an old sheet,

and ironed the diagonal  crease into them.

With rectangles, I need half of them to go left to right, like the one above,

and the other half to go right to left.

I cut 1.5 inch strips of a couple of beige prints, 

ironed them right sides together lengthwise,

and they laid the crease of the beige strip into the crease of the foundation.

I top stitched it in a matching thread right down the crease so the strips don't shift.

I want these strips to match up and make diamonds,

although I don't care if the other strips are various sizes or a bit wonky.

I'm cutting these 6.5 by 9.5 inches, so I make sure the strip is longer than the background.

Then I sew the brights onto the right side of the beige strips 

until I've completely covered the foundation, 

and trim the blocks from the back to 6.5 by 9.5 inches.

Repeat for black strips.

I've finished 16 blocks,

and have to sew black prints onto 32 more.

I may make this one row or one column bigger.

With 12 diamonds, it measures 48 by 54.

I would like it to finish at a throw size, 

so it's either more blocks,

or using up black strips for a piano key border.