Print either the "small" or "large" version of the trick. I recommend using the small version as the smaller blocks are less likely to tip over as you load them into the box. While there's nothing wrong with them tipping over, it is annoying and makes it look like you are fumbling or doing something tricky. On the other hand, if you want such an effect -- then use the large version!

The large version uses six 20x20mm blocks while the small version uses six 20x14mm blocks. Not surprisingly, it will take you less time to print the smaller version.

Small Version
1. Print pin.stl (same file works for either the small or large version).
2. Print six copies of small-block.stl. It looks best if you print each one a different color.
3. Print the box top and bottom: use either small-box.stl or the individual small-lid.stl and small-bottom.stl files. If you have problems with the print curling at the edges, then you may be better off printing the two pieces separately as that will have them closer to the center of your build platform.
4. You can use the magic-blocks.scad file to tweak any of the parts to your liking.

Large Version
1. Print pin.stl.
2. Print six copies of larger-block.stl. The trick looks best if you print each one a different color.
3. Print the box top and bottom: use either large-box.stl or the individual large-lid.stl and large-bottom.stl files. If you have problems with the print curling at the edges, then you may be better off printing the two pieces separately as that will have them closer to the center of your build platform.
4. You can use the magic-blocks.scad file to tweak any of the parts to your liking.

Performing the Trick
To perform the trick,

1. Start with the blocks in the box with the pin running through them. Show the audience how the pin traps the blocks in place, preventing their removal.
2. Remove the pin and dump the blocks out. Allow the audience to inspect the blocks, box and pin.
3. Choose a volunteer from the audience to select two of the six blocks.
4. Using the lid to obscure the audience's view, return all six of the blocks to the box. However, place the two selected blocks in at 90 degrees from the other blocks:

| | |===| | |
| | |===| | |
     ^^^ Two selected blocks
 ^^^      ^^^ Remaining 4 blocks

5. Close the box with the lid.
6. Pierce the blocks with the pin,

  | | |===| | |
----------------o  Pin
  | | |===| | |

7. Show the audience that all the blocks, including the chosen ones, are still in the box by letting them see the blocks through the peep holes in the box's lid and bottom.
8. Turn the box upside down but holding the lid in place.
9. Release the lid, allowing it and the two selected blocks to magically drop out of the box.
10. Show that the other blocks remain pinned! Jiggle the box a little if you need to prevent the audience from seeing the large gap left behind by the two selected blocks. Point being to not have them realize that those two blocks were put in sideways.
11. Take a bow or begin another trick such as Thing 24719, the magic coin piercing trick which you can also print!