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).

TrackStar

Parallelian -- from Wolfram MathWorld

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

Parallelian -- from Wolfram MathWorld

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

Triangle Counting -- from Wolfram MathWorld

Fuhrmann Triangle -- from Wolfram MathWorld

PDF) Congruent triangles in arrangements of lines

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

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

Eigencenter -- from Wolfram MathWorld

Central Triangle -- from Wolfram MathWorld

Math Games: Kobon Triangles

MEDIAN Don Steward mathematics teaching: Kobon triangles