Kobon Triangle -- from Wolfram MathWorld

Kobon Fujimura asked for the largest number N(n) of nonoverlapping triangles that can be constructed using n lines (Gardner 1983, p. 170). A Kobon triangle is therefore defined as one of the triangles constructed in such a way. The first few terms are 1, 2, 5, 7, 11, 15, 21, (OEIS A006066). It appears to be very difficult to find an analytic expression for the nth term, although Saburo Tamura has proved an upper bound on N(n) of |_n(n-2)/3_|, where |_x_| is the floor function (Eppstein).

Kobon Triangle -- from Wolfram MathWorld

Kobon Triangle -- from Wolfram MathWorld

PDF) Congruent triangles in arrangements of lines

Kobon Triangles

Kobon Triangles: number of nonoverlapping ?s from $n$ lines - Online Technical Discussion Groups—Wolfram Community

Fuhrmann Triangle -- from Wolfram MathWorld

Obtuse Triangle -- from Wolfram MathWorld

Central Triangle -- from Wolfram MathWorld

Altitude -- from Wolfram MathWorld

Parallelian -- from Wolfram MathWorld

TrackStar

How to draw a Pascal triangle up to n=20 - Quora

Kobon Triangle -- from Wolfram MathWorld