The geometry of megakaryocyte mitoses. Mitotic figures of 8N, 16N and 32N megakaryocytes as found in tissue sections of bone marrow biopsies (A,E,I); proposed geometries (B,F,J); and comparison of proposed to actual figures (C and D, G and H, K and L). The approximate locations of the centrosomes are denoted by colored circles, and the metaphase plates by black rings (in C,G,K). Sometime the anterior- or posterior-most metaphase plate was out of the plane of the section. The figure with 4 vertices (B) is a tetrahedron. The figure with 8 vertices (F) is called a stella octangular, but the vertices of this figure form the corners of a cube (G). The figure with 16 vertices (J) is a geodesic that has four 6-faceted vertices, and twelve 5-faceted vertices and is essentially comprised of four 6-faced (hexagonal) surfaces. These are color coded (left, aqua/blue; right, lime/green; bottom, pink/red and back, yellow/canary) with the center represented by solid circles and the shared edges by 2 colored circles of appropriate colors. The actual 32N image is likely distorted or collapsed somewhat, allowing it to be captured in a single tissue section.