# [APL(Dyalog Unicode)][1], <sup><s></s></sup> <strike>58</strike> 56 bytes <sup>[SBCS][2]</sup>

-2 bytes due to unused variable assignment `B←`.

A dfn that takes the number of edges and outputs a bitmap of the shape.

````
{(C-C⊖⍨⌈⍵÷2)∧.>⍥|C∘.-I∘.+0J1×I←40÷⍨¯41+⍳81⊣C←¯1*⍵÷⍨+⍨⍳⍵}
````

It uses complex numbers to encode points on the 2D plane.

````
{(C-C⊖⍨⌈⍵÷2)∧.>⍥|C∘.-I∘.+0J1×I←40÷⍨¯41+⍳81⊣C←¯1*⍵÷⍨+⍨⍳⍵}
                                           C←¯1*⍵÷⍨+⍨⍳⍵  ⍝ vertces
                     I∘.+0J1×I←40÷⍨¯41+⍳81               ⍝ points on the plane
                 C∘.-                                    ⍝ displacement vectors to the vertices
 (C-C⊖⍨⌈⍵÷2)                                             ⍝ displacement vectors between oppisite vertices
            ∧.>⍥|                                        ⍝ are the points within the reuleaux polygon
````

[Try it on APLgolf!](https://razetime.github.io/APLgolf/?h=AwA&c=q9Zw1nV@1DXtUe@KRz0dj3q3Ht5upPmoY7me3aPepTXOjzpm6Ol6gkhtAy/Dw9M9H7VNMDE4vB2o/NB6E0PtR72bLQwfdS12BoofWm@oBTYAKKkNMq93M5BbCwA&f=S3/UNqHaSF9dT1k92lD7Ue/W2FqFR71zFUryFdLyi3ITSxRKMlIVkjJLchMLuNIV0hSMwaQpmDQHk5ZcAA&i=AwA&r=tryapl&l=apl-dyalog&m=dfn&n=f)

[1]: https://dyalog.com
[2]: https://github.com/abrudz/SBCS