Tweetcart https://twitter.com/0xSim/status/1392363380476944386

sunrect.lua

function sunrect()
  -- rainbow palette
  pal({1,-15,-13,3,-5,11,-6,10,9,-7,8,-8},1)
  -- origin x,y and radius
  ox,oy,r=64,64,60
  ::_::
  cls()
  -- 12 points for the 12 colors
  for i=1,12 do
    -- the 12 points are equally spread on the circle's top half
    -- 0.5 / 12 = ~0.041
    a=i*.041

    -- anchor point (rect's top left) for the current color
    x=ox+cos(a)*r
    y=oy+sin(a)*r

    -- "mirror" point (rect's bottom left), that will run around the circle in about 5 seconds
    lx=ox+cos(a+t()/5)*r
    ly=oy+sin(a+.5+t()/5)*r

    -- line vector
    dx=x-lx
    dy=y-ly

    -- calculate rect's bottom right
    len=4/sqrt(dx^2+dy^2) -- the rect has a width of 4px
    dx*=len
    dy*=len

    -- top left > bottom left
    line(x,y,lx,ly,i)
    -- > bottom right
    line(lx+dy,ly-dx)
    -- > top right
    line(x+dy,y-dx)
    -- > top left, to close the rect
    line(x,y)
  end
  flip()
  goto _
end