Solution for Oskar's Big Knot Variation puzzle

These images depict the assembly process of Oskar van Deventer's Big Knot Variation puzzle. Pieces that are "new", or have been moved are drawn in green, others are drawn in brown. (Drawings by Oskar.)
There are four different kinds of pieces used in Big Knot Variation:

The letters that are shown on the ends of the pieces are for identification in these images; they are not present on the pieces of the real puzzle.
The puzzle consists of 6 pieces of type A, 6 of type B, 1 of type C and 1 of type D.

Take two pieces of type B and position them on your working surface like this:

Insert a third piece of type B:

Insert the piece of type D, the "long end" of the hole in the piece should be at the top:

Insert piece C with the opening at the top:

Insert two pieces of type A:

Insert four pieces of type A (to accomplish this, you'll have to lift the sub-assembly consisting of piece C and two pieces of type A a bit):

Insert two pieces of type B, then slide the piece of type D down.

Insert the last piece of type B:

Slide the piece of type D back up:

That's it.