The HOW TO
First the pattern: one can use any shape of house, note that the distance x on the "front/back of the house" piece, is to be reported on the pattern of the "side of the house" like shown on the pictures.
First I choose two fabrics that I sew together to make the front/back pieces and the roof, same for the side pieces of the house
I then cut the pieces with 5 mm of seam allowance. Cut the decorations and start sewing them on the front pieces
Sew two velcro straps on the side pieces
Then I sew all four sides together along the dotted line. I don't sew until the end of the roof piece but stop 5 mm before the end.
And finally the bottom/base. I cut a square that was 1cm larger than the measurement of the width of the house (including 2x5mm seam allowance). Then pin and sew only from seam to seam, so as to be able to sew 3 sides - as per the orange dotted line.
Finished result, that needs to be turned inside out, from the fourth side of the base that has been left open
Now I sew a little cushion, with two squares of the same dimension as the one cut for the base, I sew it along the green dotted line, cut the corners, turn it inside out
Fill it with lenses and machine stitch along the yellow dotted line
I then fill the house with filling material, until it is fully stuffed. Then I insert the "lenses bag" at the bottom and handstitch the opening.