[math-fun] 24-cell --- it sez 'ere ...

At https://en.wikipedia.org/wiki/24-cell we are informed that << The 24-cell is the unique convex regular Euclidean polytope that is neither a polygon nor a simplex. Relaxing the condition of convexity admits two further figures: the great 120-cell and grand stellated 120-cell >> The first sentence is plainly false as it stands (eg. octahedron, tesseract); the second (sic: missing period) yields me no clue as to what might instead have been intended by the first. Any ideas out there? WFL