Here is a rectangle turned out.
The size of the patchwork top is 25x20 cm.
Polyester batting - 25x20 cm and the lining is a little longer (later we'll bend it) 25x22 cm
Sew the neck of the bag. I have two pieces of fabric, you can take a whole piece.
First, we will process the side parts, then we will arrange the top - there we will miss the string drawstring.
I have a size of 10x25 cm, but it is better to take it narrower, for example, 8x25 cm
Again, collect the sandwich: the neck of the bag + base + bias binding. Bottom also needs to be processed by the bias binding.
We fold our tuba face in and sew.
Fold the side stock and hem.
We sew all the bias binding, better by hand.
Sew hands to the bottom of the bag, turn out.
Thread the string and set the clamp.