How can you arrange 16 triangles so there are 10 rows of 4 triangles each?

......A..B...C...D.. E...1...2...3...4... F...5...6...7...8... G...9..10..11.12. H..13..14.15.16. There are ten rows - A, B, C and D, going downwards - E, F, G and H going across, and 1,6,11 and 16 & 4, 7, 10 and 13 going diagonally.