The following used to produce three parallel lines.

Now it produces one straight line and two arcs.

\starttext

\startMPcode
z0 = origin;
z1 = 72dir(45);
dotlabel.bot("z0", z0);
draw z0--z1;
draw (z0--z1) paralleled -15 withcolor red;
draw (z0--z1) paralleled 15 withcolor blue;
\stopMPcode

\stoptext