Local dimension maps in log-polar coordinates for gas (leftmost panel) and stars of different ages (younger than 0.5 Gyr, 0.5–2 Gyr old, 3–8 Gyr old, and older than 10 Gyr, from left to right) at time 13 Gyr. The azimuth increases in the direction of rotation. Contours of D = 1.9 (dashed) and D = 2 (solid) are overplotted. Radii 4 and 8 kpc are indicated with dotted white lines.