Answers.Body: <p>To answer your second question: The technique was used by Lego in 1976's <a href="https://brickset.com/sets/726-1/Western-Train" rel="noreferrer">set 726</a> (12v Western train with 2 Wagons and Cowboys), to attach the horse's tail.</p>
  <p>See <a href="http://www.peeron.com/scans/726-1/13" rel="noreferrer">page 13</a> of the instructions:</p>
  <p><a href="https://i.sstatic.net/re0PL.png" rel="noreferrer"><img src="https://i.sstatic.net/re0PL.png" alt="Steps of instructions showing the technique" /></a></p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-08-11T20:24:01.917Z
Answers.Text: Amazing! And look at the old legs used for the horse, too!
Answers.UserDisplayName: RSchulz
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-08-12T14:38:38.917Z
Answers.Text: I'm not quite sure this is still legal, keeping in mind 46 years have passed since quoted use in 726 set. There are cases where TLG used certain building techniques, but then marked them as "illegal".
Answers.UserDisplayName: Alex
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-08-12T20:10:29.383Z
Answers.Text: @Alex: That's why I didn't venture an opinion on the 'is this [currently] "legal"?' part of the question.
Answers.UserDisplayName: john_e
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-08-21T22:51:03.230Z
Answers.Text: Great find! I remembered this technique from when I was a kid, but didn't know if it was in a set, or discovered by me. I could only find 'plate between studs' connections.
Answers.UserDisplayName: Matthew Jensen
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-08-11T15:21:39.260Z
Answers.LastActivityDate: 2022-08-11T16:40:52.137Z
Answers.LastEditDate: 2022-08-11T16:40:52.137Z
Answers.UserDisplayName: john_e
Answers.Body: <p>Some anecdotal evidence against legality: I have built such connections with rather old plates a long time ago and one of the outer plates failed (the wall breaking off). So it certainly puts the plates under some stress.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-08-18T13:13:57.623Z
Answers.LastActivityDate: 2022-08-18T13:13:57.623Z
Answers.UserDisplayName: Sir Cornflakes
Body: <p>This is closely related to the question about <a href="https://bricks.stackexchange.com/questions/17334/">jamming plates underneath 2x2 <em>round</em> bricks</a>, (and indeed prompted by <a href="https://bricks.stackexchange.com/questions/17334/#comment22811_17334">a comment there</a>), with differences explained later.</p>
  <p>It is possible to attach a plate (or tile) to the underside of a <s>square</s> rectangular brick/plate/tile, between the wall and the tubes, like so:</p>
  <p><a href="https://i.sstatic.net/EjwXV.jpg" rel="noreferrer"><img src="https://i.sstatic.net/EjwXV.jpg" alt="plates connected to the underside of different bricks" /></a></p>
  <p>Note how the distance between a brick's wall and its inner tube seems to be the same as the thickness of a plate:</p>
  <p><a href="https://i.sstatic.net/JugZf.png" rel="noreferrer"><img src="https://i.sstatic.net/JugZf.png" alt="detail of plate inserted into transparent brick" /></a></p>
  <p>A few observations:</p>
  <ul>
  <li><p>This connection <em>feels</em> looser (seems to have less clutch) than using a round brick.</p>
  </li>
  <li><p>For 1-stud-wide plates, this connection doesn't guarantee a straight angle. The edge of the plate sits loose inside the brick.</p>
  </li>
  <li><p>For post-2005 regular bricks (i.e. non-sloped), since they have thinned walls with notches at every stud, the connection is particularly flimsy. A 1-stud-wide plate just won't get any grip at all.</p>
  </li>
  <li><p>The walls of rectangular bricks are connected to each other, so bending a wall &quot;outwards&quot; (to jam a plate/tile inside) means bending or stressing the perpendicular walls (as far as I understand the physics of solid materials).</p>
  </li>
  </ul>
  <p>So:</p>
  <ul>
  <li><p>Is this connection &quot;legal&quot;? (i.e.: Does this connection stress the parts involved?)</p>
  </li>
  <li><p>Has this type of connection been used in any official sets?</p>
  </li>
  </ul>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-08-06T14:47:27.493Z
Comments.Text: I'm guessing the "thinned walls" comment is the key indication that Lego doesn't consider it legal - otherwise they'd have had to preserve the old style of wall.
Comments.UserDisplayName: RSchulz
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-08-07T23:15:48.397Z
Comments.Text: Would this connection be considered "in system"? it seems the parts are offset by half a plate in two dimensions, and half a stud in the other, which would be in system.
Comments.UserDisplayName: Matthew Jensen
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-08-07T23:25:05.800Z
Comments.Text: Indeed - the offset is 4 LDUs (half a plate) in two axes. The plate, however, can slide along the third axis. This becomes obvious when using a 2x8 brick: a plate/tile can slide between the wall and the tubes.
Comments.UserDisplayName: IvanSanchez
Tags: <building><connections>
Title: Plate perpendicular to bottom of square brick/plate: is this connection legal?
UserDisplayName: IvanSanchez
ThreadText: # Plate perpendicular to bottom of square brick/plate: is this connection legal?
  
  (Asked by: username_0 on 2022-08-05)
  
  This is closely related to the question about [jamming plates underneath 2x2 *round* bricks](https://bricks.stackexchange.com/questions/17334/), (and indeed prompted by [a comment there](https://bricks.stackexchange.com/questions/17334/#comment22811_17334)), with differences explained later.
  
  It is possible to attach a plate (or tile) to the underside of a ~~square~~ rectangular brick/plate/tile, between the wall and the tubes, like so:
  
  [![plates connected to the underside of different bricks](https://i.sstatic.net/EjwXV.jpg)](https://i.sstatic.net/EjwXV.jpg)
  
  Note how the distance between a brick's wall and its inner tube seems to be the same as the thickness of a plate:
  
  [![detail of plate inserted into transparent brick](https://i.sstatic.net/JugZf.png)](https://i.sstatic.net/JugZf.png)
  
  A few observations:
  
  * This connection *feels* looser (seems to have less clutch) than using a round brick.
  * For 1-stud-wide plates, this connection doesn't guarantee a straight angle. The edge of the plate sits loose inside the brick.
  * For post-2005 regular bricks (i.e. non-sloped), since they have thinned walls with notches at every stud, the connection is particularly flimsy. A 1-stud-wide plate just won't get any grip at all.
  * The walls of rectangular bricks are connected to each other, so bending a wall "outwards" (to jam a plate/tile inside) means bending or stressing the perpendicular walls (as far as I understand the physics of solid materials).
  
  So:
  
  * Is this connection "legal"? (i.e.: Does this connection stress the parts involved?)
  * Has this type of connection been used in any official sets?
  
  **Tags:** building, connections
  > **Comments:**
  > **username_1**: I'm guessing the "thinned walls" comment is the key indication that Lego doesn't consider it legal - otherwise they'd have had to preserve the old style of wall.  
  > **username_2**: Would this connection be considered "in system"? it seems the parts are offset by half a plate in two dimensions, and half a stud in the other, which would be in system.  
  > **username_0**: Indeed - the offset is 4 LDUs (half a plate) in two axes. The plate, however, can slide along the third axis. This becomes obvious when using a 2x8 brick: a plate/tile can slide between the wall and the tubes.  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_3 on 2022-08-11. Score: 9
  
  To answer your second question: The technique was used by Lego in 1976's [set 726](https://brickset.com/sets/726-1/Western-Train) (12v Western train with 2 Wagons and Cowboys), to attach the horse's tail.
  
  See [page 13](http://www.peeron.com/scans/726-1/13) of the instructions:
  
  [![Steps of instructions showing the technique](https://i.sstatic.net/re0PL.png)](https://i.sstatic.net/re0PL.png)
  
  > **Comments:**
  > **username_1**: Amazing! And look at the old legs used for the horse, too!  
  > **username_4**: I'm not quite sure this is still legal, keeping in mind 46 years have passed since quoted use in 726 set. There are cases where TLG used certain building techniques, but then marked them as "illegal".  
  > **username_3**: @Alex: That's why I didn't venture an opinion on the 'is this [currently] "legal"?' part of the question.  
  > **username_2**: Great find! I remembered this technique from when I was a kid, but didn't know if it was in a set, or discovered by me. I could only find 'plate between studs' connections.  
  
  ---
  
  ### Answer by username_5 on 2022-08-18. Score: 4
  
  Some anecdotal evidence against legality: I have built such connections with rather old plates a long time ago and one of the outer plates failed (the wall breaking off). So it certainly puts the plates under some stress.
  
  
  ---
  
  