1. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

2. Draw a third line parallel to, and equidistant between, the first two lines.

3. Draw a two more lines parallel to the three lines so that you now have five equally spaced lines.

4. Decide which base pair you will draw, and on which side you will have the purine base and on which side you will have the pyrimidine base.

5. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

6. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

7. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

8. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

9. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

10. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

11. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

12. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

13. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

14. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

15. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

16. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

17. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

18. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

19. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

20. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

21. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

22. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

23. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

24. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

25. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

26. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

27. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

28. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

29. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

30. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

31. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

32. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

33. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

34. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

35. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

36. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

37. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

38. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

39. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.

40. Draw two parallel lines that are spaced vertically about the size you intend to draw the Watson-Crick base pair.