`line.divideAt(t)`

Divide the line into two lines at the point that lies `t`

(normalized length) away from the beginning of the line.

Returns an array with two new lines without modifying the original line. For example, if `t`

equals `0.5`

, the function returns an array of two lines that subdivide the original line at its midpoint.

The function expects `t`

to lie between 0 and 1; values outside the range are constrained to 0 and 1, respectively.