\documentclass{standalone}
\usepackage{luamplib}
\begin{document}
\mplibtextextlabel{enable}
\begin{mplibcode}
def equilateral_triangle_point(expr a, b) =
a rotatedabout(b, 60)
enddef;
primarydef o beyond z = z scaled (1+o/abs(z)) enddef;
beginfig(1);
randomseed := 543.01811;
pair A, B, C, D, E, F, G, H, I;
A = 91 dir ( 0 + 18 normaldeviate);
B = 92 dir (120 + 18 normaldeviate);
C = 93 dir (240 + 18 normaldeviate);
D = equilateral_triangle_point(A, B);
E = equilateral_triangle_point(B, C);
F = equilateral_triangle_point(C, A);
G = 1/3(A + B + D);
H = 1/3(B + C + E);
I = 1/3(C + A + F);
draw A -- B -- C -- cycle withcolor blue;
draw A -- D -- B -- E -- C -- F -- cycle withcolor 3/4;
draw G -- H -- I -- cycle withcolor 2/3 red;
