Most classic toys started out being made of wood. Legos were after all made by a carpenter.
Making system sized bricks is quite a challenge because they have thin spots. Duplo or quarto or would be a bit easier.
It will take a little skill and patience but making your own legos is worth it.
This method requires no special tools(but if I had a mill I would mill them out)
Step 1: Plot It Out
A fine amount of accuracy is needed to insure the bricks clip to one another and their plastic counterparts.
I measured the bricks with a caliper and got some good measurements. I provided them in millimeters, inches and fractional inches (to the nearest 1⁄16 so it may not clip to plastic blocks)
The right view is shown only for completeness (it is not needed for dimensioning)
Step 2: Drilling
Drilling holes in the stud locations not only allow placement of the dowel stud,
but it is where the studs of other bricks clip in. This means the placement is very critical.
a 3⁄16 drill bit is the bit I used.
I strongly suggest leaving space around the actual brick so it does not fracture.(trims nice later)
Making an indent with the drill bit or an awl, or center punch will make it a little easier.
(I cheated and used a thin piece of plastic as a template so I only had to plot once)
Step 3: The Studs
A piece of 3⁄16 dowel works quite well for the studs (same as the drill bit). The length is not to important
I cut them about 1⁄4 (7mm) length, just eyeballing it. Then chamfer at least one end (makes it easier to put in)
It is best to run the dowel through a 3⁄16 hole in a piece of metal or plastic to size it.
The dowel was a little larger than 3⁄16 which causes problems putting them in.
I used a punch and hammer to gently nudge the studs in their holes.
If they are angled try to straiten them by tapping the higher side.
Step 4: Finishing
After all studs are put in, the block can be cut out of the rough cut.Before you do clip a brick into the bottom
to widen the holes.(start with a 1 stud brick then a 2x2 then 4x4 or use the flat end of the bit)
A 1x2 stud is the smallest I have made. I do not see a 1x1 happining.
I used a rotary tool to cut out the bricks, with a diamond disc it cuts and sands(and burns if your not careful)