I am defining illegal as it is in this answer, specifically the following

  • Studs-on-side bricks cannot have their side stud in the hole of a technic brick
  • Bricks mounted SNOT style onto Ehrling/Headlight bricks cannot sit directly above a normal stud (the minimal height of the LEGO embossing makes that combination illegal)
  • Technic pins have to be fully inserted into technic holes, otherwise they stay in compressed state which causes stress on the element.
  • Plates cannot be inserted with their studs into technic bricks, unless it is a 1x1 plate (so only 1 hole is used) and there is no brick attached to the technic brick directly above the inserted plate.
  • As mentioned by you already, you cannot insert plates between studs (this used to be a valid technique 20+ years ago, but is no longer considered "legal" by LEGO).

I am also including one other situation:

A round piece between four studs as stated in a comment by Sandra.

When, if ever, have any of these methods been used in an official Lego Build?

  • 5
    Have you checked presentation made by LEGO designer Jamie Berard posted in the same answer you are referring to? It has examples.
    – Alex
    Commented Mar 27, 2021 at 6:47
  • Yeah, that file even shows a few (old) times when lego used an illegal technique. Although after each time they admitted that it's illegal. Commented Mar 27, 2021 at 14:24
  • Does this answer your question? What are some "Illegal" LEGO combinations?
    – Alex
    Commented Mar 27, 2021 at 18:13
  • @Alex I literally have an answer to that question linked. Commented Mar 27, 2021 at 20:15
  • 2
    If the question were about the different types of illegal techniques, it would indeed be a duplicate. But it asks about usages of such techniques in official sets, which is completely different in my eyes, so I vote leave open.
    – zovits
    Commented Mar 28, 2021 at 14:29

2 Answers 2


As mentioned by you already, you cannot insert plates between studs (this used to be a valid technique 20+ years ago, but is no longer considered "legal" by LEGO)

This technique is used in 21309 Saturn V, to mount the flag piece as part of the moon diorama.

Given this set was released in 2017, I’d say its definitely a modern usage.

step 325

  • 5
    It's a tile and not a plate... tiles wedged between studs aren't considered illegal, however studded plates are problematic as the lego logo embossed on the studs of the bottom plates protrude against the studs of the wedged plate... Commented Mar 29, 2021 at 10:53

The 1x1 round piece between 4 studs is used in the part of the Y-wing extra in set 4489. The extra build came across the 4 sets 4488-4491.

enter image description here

Remember getting this as a child and not being able to finish the Y-wing because I couldn't place this piece, definitely feels illegal.

  • What you describe here is not related to placing a piece in any sort of ways that would result in damaging any of the pieces in contact or being unable to disassemble, which is usually meant by "illegal" building technique.
    – Alex
    Commented Jan 1, 2023 at 21:24
  • 1
    I found this question unanswered when trying to know whether it’s illegal. And OP specifically asks for an example of exactly this, which I provided. Do you know of any other sets where this technique is used? Commented Jan 2, 2023 at 14:25
  • My bad. I read your answer incorrectly first time - I assumed you mention an extra piece used to build additional model, which is not part of the base models, but is present as "extra". So I took a liberty on updating your answer to reflect this issue.
    – Alex
    Commented Jan 2, 2023 at 14:53

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