To recreate this fun and easy procedure at home all you need are:

A piece of wood: 50cm long, 8cm wide and 4cm thick
A wood cutting saw
A tube of wood filler
A wooden tongue depressor or popcicle stick: 10-12cm long, 1-2cm wide and 20-40mm thick (approx.)
4 carpentry or finishing nails: 2.5cm long
A hammer
A measuring device: tape measure or graduated meter stick
A number 2 graphite pencil (eraser optional)
Work gloves (for both hands)
Safety goggles (for both eyes)
A human assistant: equipped with work gloves and safety goggles
(most if not all of these items can be found in the seldom used closet of any home)

The procedure: (as may be performed by an ambidextrous human)
This procedure is longer and takes more preparation than the reparation of the broccoli tendon

Note:
If the sight of sawdust makes you nauseous, this procedure is not for you.

Place the piece of wood on a clean, unencumbered, level work surface with the long and wide portion in contact with the work surface.
Using the number 2 graphite pencil, print the word BOTTOM at the leftmost end and the word TOP at the rightmost end of the piece of wood,
in the center of the piece of wood print the word FRONT.

Turn the piece of wood 90 degrees, onto the 4cm thick edge, with the word FRONT facing away from you.

In the center of the piece of wood print the word INSIDE with the number 2 graphite pencil (on the 4cm, skyward facing edge).

Turn the piece of wood 90 degrees, so that the word FRONT is in contact with the work surface.

In the center of the piece of wood print the word BACK with the number 2 graphite pencil.

Turn the piece of wood 90 degrees, onto the 4cm thick edge, with the word BACK facing away from you.

In the center of the piece of wood print the word OUTSIDE with the number 2 graphite pencil (on the 4cm, skyward facing edge).

Turn the piece of wood 90 degrees, so that the word FRONT is facing skyward.

Using the number 2 graphite pencil and the measuring device,
draw a straight line around the circumference of the wood at a distance of 6cm from the TOP.

This is the controlled fracture line (heretofore referred as CFL) and indicates the future site of the controlled fracture.

Place the piece of wood flat on the work surface with the word FRONT facing skyward and TOP to your right.

Using the number 2 graphite pencil and the measuring device, measure along the CFL, 4cm from the FRONT / INSIDE edge
towards the FRONT / OUTSIDE edge and mark this distance (the center point) with a line perpendicular to the CFL.

Place the piece of wood flat on the work surface with the word BACK facing skyward and TOP to your right.

Using the number 2 graphite pencil and the measuring device, measure along the CFL, 4cm from the BACK / INSIDE edge
towards the BACK / OUTSIDE edge and mark this distance (the center point) with a line perpendicular to the CFL.

Place the piece of wood flat on the work surface with the word INSIDE facing skyward and TOP to your right.

Place safety goggles securely over your eyes.

Place work gloves securely on your hands.

With your left hand, firmly hold the piece of wood against the work surface.

With your right hand, firmly hold the wood cutting saw (serrated edge down).

Align the serrated edge of the wood cutting saw with the CFL visible on the skyward facing INSIDE edge.

Begin sawing to a depth of 4cm (the center point) stop when you reach the perpendicular line on the CFL.

You have now completed the FRACTURE.

Using your mouth, blow the excess sawdust out of the FRACTURE.

Place the piece of wood and the wood cutting saw out of the way on the unencumbered, level work surface
(at this point it may no longer be clean).

Remove safety goggles and work gloves and place them out of the way on the unencumbered, level work surface.

Place the wooden tongue depressor or popcicle stick flat on the work surface in front of you.

Using the number 2 graphite pencil and the measuring device,
locate the midpoint of the wooden tongue depressor or popcicle stick's length
and mark the midpoint with a line.

Using the number 2 graphite pencil and the measuring device,
make a parallel line 50mm to the left of the midpoint line and another parallel line 50mm to the right of the midpoint line.

Using the number 2 graphite pencil and the measuring device,
place a dot at 1cm and 3cm from each end of the wooden tongue depressor or popcicle stick (a total of 4 dots).

These are where the finishing nails will go, so center the dots accordingly across the width.

Place the wooden tongue depressor or popcicle stick aside for now.

Place the piece of wood flat on the work surface with the word INSIDE facing skyward and TOP to your right.

Align the piece of wood so that the FRACTURE is directly in front of you.

Place the wooden tongue depressor or popcicle stick (dots and lines skyward), on the INSIDE edge of the piece of wood.

Center the wooden tongue depressor or popcicle stick's midpoint line over the FRACTURE of the piece of wood.

Using the 4 carpentry or finishing nails and the hammer,
gently tap the nails into place on all the dots so that they pierce the wooden tongue depressor or popcicle stick,
but don't penetrate the piece of wood beneath.

Align the wooden tongue depressor or popcicle stick's rightmost line over the FRACTURE of the piece of wood.

Using the hammer, drive in completely the two nails to the right of the fracture.

Place the piece of wood so that the CFL is at the edge of the work surface, with the TOP hanging over the edge.

Using the human assistant, have the human assistant firmly hold the piece of wood against the work surface.

With your right hand press the TOP of the piece of wood until the FRACTURE opens 1cm.

When the leftmost line of the wooden tongue depressor or popcicle stick is aligned with the leftmost edge of the fracture,
drive in completely the two leftmost nails.

Thank the human assistant, and ask them to release the piece of wood.

Place the hammer and the human assistant out of the way on the work surface.

Place the piece of wood flat on the work surface with the word FRONT facing skyward and TOP to your right.

Open the tube of wood filler and place the cap out of the way on the work surface.

Using the tube of wood filler, fill in gap of the FRACTURE (a.k.a. the wedge) so that it is level with the FRONT.

Allow the wood filler the appropriate amount of time to dry indicated on its packaging.

Once dry, you may examine your work.
Return all materials to the seldom used closet of any home, clean up your work surface and the area around it.

Congratulations, you have successfully performed an open wedge timber osteotomy!
The finished product may appear warped, this is normal.
The intent of this procedure is to counterbalance an existing warp in the timber.