Toy box just has to be bright primary colours, right? Maybe not the obvious partner for "slashed" though... so I took the toy box theme into the design too, thinking about those shape sorting toys.
I started with red, yellow and blue fabrics over green felt. Then I filled the simple shapes with patterns of parallel lines in green thread (machine stitched, of course!). Finally the slashing - cutting the top fabric between the lines gives a slightly 3D effect as the felt tries to peep through.
I do like the light and shade effect of this technique; no surprise there, I can never resist introducing shadows into my work.