Hey, anyone knows why the lines (vertex) dont connect (seems so), when i use PGraphics?

please look at the code, guess this makes it clear what i mean...

1. PGraphics m1 = createGraphics(40,40,P2D);
2. PGraphics m2 = createGraphics(40,40,P2D);
3. background(255);
4. smooth();
5. m1.beginDraw();
6. m1.noStroke();
7. m1.fill(0,255,255);
8. m1.rect(0,0,40,40);
9. m1.endDraw();
10. m2.beginDraw();
11. m2.stroke(255,0,255);
12. m2.strokeWeight(6);
13. m2.strokeCap(ROUND);
14. m2.beginShape();
15. m2.vertex(5,15);
16. m2.vertex(15,5);
17. m2.vertex(25,15);
18. m2.vertex(35,5);
19. m2.endShape();
20. m2.endDraw();
21. image(m1,10,10);
22. for(int i = 0; i < 40; i+=15)
23. blend(m2,  0,0,40,40,   20,10+i, 40,40, MULTIPLY);
24. noFill();
25. strokeWeight(6);
26. strokeCap(CORNER);
27. translate(20,60);
28. beginShape();
29. vertex(5,15);
30. vertex(15,5);
31. vertex(25,15);
32. vertex(35,5);
33. endShape();

thanks!