Aliasing artifacts are found in this image on the edges of triangular shapes because these are high-frequency areas in the image where there is a rapid color change from one pixel to the next (i.e. from white to red in the outer spokes and pink to blue in the inner). This is why the aliasing is particularly bad at the narrow tips of the blue spokes. On the other hand there is no aliasing in the center circle due to the uniformity of color (i.e. low frequency).
Aliasing artifacts are found in this image on the edges of triangular shapes because these are high-frequency areas in the image where there is a rapid color change from one pixel to the next (i.e. from white to red in the outer spokes and pink to blue in the inner). This is why the aliasing is particularly bad at the narrow tips of the blue spokes. On the other hand there is no aliasing in the center circle due to the uniformity of color (i.e. low frequency).