[test] failing test for finding sequence
[impl] point-support
[impl] add grid-slice concept
[impl] add grid-equal-row concept
[impl] start checking for equal lines
[fix] count may be equal to 4, too
[refac] remove clutter
[refac] return lenght, not list
[refac] count, dont transform
[refac] use point_count iso direct sum
[refac] use lambda iso local function
[tidy] whitespace, remove unneeded function
[tidy] reorder imports
[refac] rename function
[tidy] move core function upfront
[test] add failing test
[test] add failing test
[fix] in_grid( (-1, _) ) returns true, falsely.

points are not in grid when coords are negative