Extended Data Fig. 3: Skyrmion number of the skyrmion bag and the skyrmion cluster inside the bag as a function of the twist angle for the skyrmion bags with 19 (a), 7 (b) and 1 (c) skyrmions in the bag.

The skyrmion numbers are calculated by integrating the skyrmion number density. For the total bag, the integrated area is given by the enclosed space inside the green dashed line of Fig. 4c, f. The skyrmion cluster only counts the skyrmions inside the bag which means that the skyrmion number density is integrated within the area surrounded by the orange line of Fig. 4c, f. For the three different skyrmion bags, both skyrmion numbers remain constant over a wide range of twist angles.