Example of simulation-issued data: a 2D image from a 2D simulation (left) and a 3D cube (right) from a 3D simulation. These data are built by dividing an N-body simulation snapshot into pixels (or voxels) and counting the particles within each, creating a discrete density map. The map is then smoothed with a Gaussian filter and log-transformed, allowing cosmic structure to stand out starkly. This process creates data that are compatible with convolutional neural networks, which specialize in feature detection.