\documentclass[border=5mm]{standalone}
\usepackage{luamplib}
\begin{document}
\mplibtextextlabel{enable}
\begin{mplibcode}
input colorbrewer-rgb
beginfig(1);

  numeric u;

  u = 42;   

  z0 = (0, 3u);
  z1 = z0 rotated 120;
  z2 = z1 rotated 120;

  z3 = z0 shifted (1/2u, 3/2u * sqrt(3));
  z4 = z3 shifted (-u,0);

  z5-z4 = whatever * (z0-z1);
  z6 = whatever [z0, z2];  
  y5 = y6 = y2 - sqrt(3) * 1/2 u;

  z7-z3 = whatever * (z0-z1); 
  z7 = whatever [z1, z2]; 

  path vii;
  vii = z3--z4--z5--z6--z2--z7--cycle;

  for i=0 upto 2: 
    fill vii rotated 120i withcolor Blues[9][i+2];
  endfor
  for i=0 upto 2: 
    draw vii rotated 120i;
  endfor

endfig;
\end{mplibcode}
\end{document}
