WPC Part12 - Hungaricum, Dotted Snake

The Dotted Snake is a snake variation invented by me. I have already shown this type on the 14th WPC. I'm not sure, but I think I found out this genre in 2003. The last year was pretty succesful for this type.
Serkan Yürekli used this genre in two tests (Puzzle Jackpot, Snake variation contest).
We could see it in Vladimir Portugalov's Fortsmarts contest.
And in two sets on the 24 hours puzzle championship. Finally I created some puzzles for the WPC.

I love creating Dotted Snake without black squares. The numbers outside the grid provide informations just about the 3rd cells, so the 2/3 part of the snake can move freely, just the body of snake and the black squares fix them.

Rules:

There is a N units long snake hiding in the grid. The body of the snake cannot touch itself, not even diagonally. Every 3rd square (3, 6, 9 etc.) of the snake has a dot on it. Numbers outside the grid reveal how many dots of the snake are in the corresponding row or column. The head, middle and tail squares of the snake are given. The black squares are not part of the snake. 

ooooooo

Some puzzles from me

There were 9 puzzles in the WPC's Play off. None of them was Dotted Snake. However the Dotted Snake was the extra puzzle. That puzzle is here: