\startMPcode{doublefun}
%\startMPpage
numeric count, temp[], tt, minus, u; u := 1cm;
path p,q,r;
pair A,B,C,D;
string varName, ss, pos[];
p := unitsquare xyscaled (8u,3.5u);
draw p;
pos[0] := "bot";
pos[1] := "rt";
pos[2] := "top";
pos[3] := "lft";
varName := "yxwz";
count := 0;
pickup pencircle scaled 5pt;
for i = 0 upto 3:
drawdot (point i of p);
draw lmt_text[
text = "$" & char(65+i) & "$",
anchor = pos[i],
offset = 2pt,
position = point i of p,
];
endfor;
%\stopMPpage
\stopMPcode