/ (0-3, 3-6, 6-9, 9-12 .) . .
.
- 0-3 . - 40 . 3-6 . - 60 . 6-9 . - 80 . 9-12 . - 100 .
"" -
"" |
https://www.youtube.com/watch?v=VUl0NE3Lwuc&t=8s
: | / |