Movie 7.

Spindle versus cell long axis orientations. All 79 cell divisions classified in Cad/MT movie CJ_4 are portrayed in 20 s frame intervals from −11.7 mins to 0 mins, the frame before the mother cell splits into two daughters. The mother cell centroid is set to the centre of each square neighbourhood, which has been rotated so that the embryonic AP axis is horizontal (unlike Supplementary Movie 2). Magenta is E-Cadherin and green is Jupiter (MTs). Mitotic spindles can be seen appearing after NEBD at around −7 mins and elongating during anaphase from around −2.5 mins. Overlaid on each focal cell centroid 6 is a black line representing the orientation and strength of elongation (see Fig. 4e, f for scale bars). Though there are exceptions, on average spindles are towards AP (horizontal) of cell long axes.