# Lego Deltoid and Astroid

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## Introduction: Lego Deltoid and Astroid

The wait is over! The double duty twofer Lego shapes Instructable has arrived! Learn how to make a cool inward curved edge triangle in the following steps. Step 5 will show you how to turn the triangle into a square (or diamond). Don't you just love twofers?

Note: I have no idea what the correct name for these curved edge shapes are but I'm sure there must be a name for them. I guess it's whatever the opposite of Reuleaux is but that may only apply to triangles. If you can tell me in the comments what to call these shapes then you will be my (whatever shape name) hero.

## Step 1: Parts

For the triangle, you will need:
-225 1x2 bricks
-an extra pair of hands or a few extra 1x2s (for step 4)

Three colors: 75 of each color

For the square, you will need:
-300 1x2 bricks
-an extra pair of hands or a few extra 1x2s (for step 4)

Two colors: 150 of each color
Three colors: 100 of each color

## Step 2:

I like making these triangles and squares because all you have to do is make a few long strips and attach them together.

Each strip is 3 rows:
25 bricks in the top row
24 bricks in the middle row
23 bricks in the bottom row

Make 3 of these beasts and you're ready for the next step.

## Step 3:

Hold two strips together as shown. Use 3 bricks to attach and close up the corner.

You'll deal with the other 2 corners like this too. Go ahead and do the second corner. If you have trouble with the third corner then you're in luck because the next step is for you.

## Step 4: Helping Hands

This is where it becomes very helpful to have an extra set of hands. It can be a little tricky closing this one up and if you aren't fortunate enough to have someone help you hold these bad boys together, don't despair. You can use a few extra bricks to support the corners and keep them from popping apart, just attach like shown in the picture. After you attach the final corner you can carefully remove these supports and no one will even know that you couldn't convince anyone to help you :)

## Step 5: Square

To make a square, all you have to do it add another strip to the triangle. It might be easier to connect the strips in pairs and then attach those together. Oh yeah and don't forget to use a few extra bricks as supports if needed.

Wish you had more Lego shapes to build? Well you're in luck:
Lego Star
L
L
ego Cog
Lego Pentagon
L
ego Triangle
L
ego Circle
L
ego Starburst
L
ego Medical Sign
Lego Heart

Also don't forget to hit that follow button so you don't miss out on the EVEN COOLER Lego shapes to come.

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## 21 Discussions

AWESOME! With links and everything! I was beginning to think that no one really knew what these were called but you can through haha. Thank you so much, I changed the title and I love that I now know what to call these and I even learned some new stuff.

I started by searching for "spirograph shapes" which is what both of them remind me of. The Wikipedia article on spirographs got me to "hypocycloids," and from there it was just a matter of reading and following links :-)

I am extremely impressed with this effort of yours on "curved walls" in LEGO. Thanks for putting so much cool stuff out there for us to see!

Have you cross-posted any of your work to the Brothers Brick? I know they generally handle models, but they do have a whole section on "technique," if you're interested.

Thank you for the kind words and it makes me happy to hear that you're enjoying my work.

I thought maybe you were just a math genius and knew the names of the shapes off the top of your head haha. I tried looking searching for stuff like "curved triangle" and "inverted circle square" but I couldn't find names for them. I love that your search started with "spirograph shapes" and ended in finding it lol.

Though I've visited that site a few times, I've never posted there. I did post to MOCpages awhile ago but the site can be very slow sometimes. There is a very strong AFOL community (adult fan of Lego) and a site that is like the Ebay of Lego (that I will not name haha) but I got a very cold reception there and a lot of the users are really rude (I think they were the nerds that got picked on in high school so now they are mean to others). I've gotten the most response on Instructables, the community is great, it's easy to share projects, and there are even prizes if you do a good project so I'll be posting all my stuff here.

I thought it was interesting that you knew about BB, do you do any Lego stuff?

When I was young, I had a huge amount of "old school" LEGO -- basic bricks, some roof (slanted) pieces and windows, and minifigs. The specialty sets, and especially the ones with big preformed shapes, were just starting to come out when I was in high school.

I didn't have the opportunity to keep my LEGO collection into adulthood, but I have made some use of it, and especially the robotics stuff, in putting together some prototypes as part of my work. The flexibility of being able to assemble and disassemble systems makes it really great to explore shapes, support systems, and even actuator options, before setting on a final design for proper machining.