There can be 5 possible slopes: -2 (high negative), -1 (low negative), 0 (no slope), 1 (low positive) and 2 (high positive)
1. At start, the slope was set to 0 (null slope) and first point was set to an arbitrary Y value.
2. Then the next point was calculated (random from 0 to 11)
- If value was <= 5, current slope was not changed
- if value was 6 or 7, slope was increased by one
- if value was 8 or 9, slope was decreased by one
- if value was 10, slope was increased by two
- if value was 11, slope was decreased by two
3. After it, slope value was limited to be between -2 and 2
4. Based on it, the next point was calculated to be Y(n+1) = Y(n) + slope*10
5. Go back to (2) until finished