Firstly, I have created the cube by drawing a square that have origin in the middle and extrude for 25mm each side and uses fillet tools to make all the corner curve 9 mm.
Moreover, I also draw a line passes through each side of the cube to make 3 axis.
I have draw a 30 mm circle in the middle on one side of the cube.
After drawing the circle I have extrude the circle to 2mm.
Create another circle which have the radius of 15mm inside the 30 mm circle and extrude to 2mm.
I have uses the tools circular pattern 2 time to fully duplicate the circle pattern to all of the side on the cube.
I have use the shell tool to make my cube become hollow and make the wall 2mm thick.
Next I ues extrude tool to delete the top part of the cube and only left with the bottom half of the cube.
I use extrude tool on the side to delete the side of the cube and only left with 1/4 of the cube.
First I have draw a 6.5 mm circle in the middle and extrude it to ceate a hole on both side of the cube.
In this step I have use the circular pattern tool 2 time to create a similar pattern on each side of the cube.
Next step is to create a hole for the pin to slot in. I have create a hole by drawing a 2 circle with 2 separate radius the first one is a circle with 7mm radius, second is the 5mm radius circle.
I have use extrude tool to half the BLOK again, which left with 1/4 of the BLOK. After that I uses fillet tool too make all the edges rounded
Create another circle between the 7 radius and 5 radius circle. This circle should have 6mm radius. After that we fillet the 6 and 5 radius circle.
do the same as the right plane for the top plane with same position and radius.
duplicate the part by using the miror tool.
Next step is to create a pin which I first create a 5.8 radius circle and extrude it to make the length 0.6 then create another circle with a length of 4.9mm radius inside the 5.8 circle and extrude it to make it a depth of 6.5 and draft 3 degree.
Create a squre with circle on top and revolve it.
Draw a rectangle in the middle and extrude it to remove the middle part. Next fillet all the edges. Duplicate on another side using miror tools.
Next is the assemble part
First is to go in the assemble page. I have name the page BLOK and added 4 piece of pin and 1 piece of BLOK.
Finally I connect all the part togather to complete the BLOK.