Most people are familiar with the mark that is on the top of the studs of LEGO® Modulex® bricks. The earliest bricks have “LEGO” on the stud and the later bricks have “M” (for “Modulex”) on the stud.
But did you know that there is more information INSIDE the brick that can tell some of its story?
The molds to make the bricks have marks inside each brick to tell what part of the mold the brick came from (I’ll post more about this practice in the future), but we also have a mark that can help us identify how old the brick is!
The very first bricks had “LEGO” on the stud and had a mark “Pat Pend” on the inside, while the patent was still in process. Once the patent was granted, the expensive molds continued to be used, but had the words “Pat Pend” scratched out!
Later, when new molds were made with the “M” on the studs, there was no mark about the patent at all.
Check out these photos of all three types of bricks.
Here are the three types of 2 x 4 bricks, the top is the oldest, with “Pat Pend” inside, and “LEGO” on the stud. The second has the “Pat Pend” scratched out, but still has “LEGO” on the stud. The final brick is a new mold and has “M” on the stud, with no mark about the patent on the inside.
Can’t see the marks? Take a closer look.
This is the oldest brick, you can see “Pat Pend” marked on the inside.
Here you can see that the “Pat Pend” has been scratched out in the mold.
This is the newer mold, with the “M” on the stud, and no mark inside about the patent.
