Index: parse.c
===================================================================
--- parse.c	(revision 11239)
+++ parse.c	(revision 11240)
@@ -232,7 +232,7 @@
 			return 0;
 		case inst2num('P','U'):
 			ctx->state.pen_down = 0;
-			p->state = ST_INST_END;
+			p->state = ST_NUMBERS_OR_END;
 			return 0;
 		case inst2num('P','D'):
 			ctx->state.pen_down = 1;
@@ -294,8 +294,10 @@
 			ctx->state.ct = coord;
 			p->state = ST_INST_END;
 			return 0;
+		case inst2num('P','U'):
 		case inst2num('P','A'):
 		case inst2num('P','D'):
+			p->state = ST_NUMBERS; /* make sure to load even a single pair */
 			if (p->argc == 2) {
 				if (ctx->state.pen_down)
 					if (draw_line(ctx, ctx->state.at.x, ctx->state.at.y, p->argv[0], p->argv[1]) < 0)