This simulation scans one shared virtual torso phantom — ribcage, two lungs, spine and an embedded soft-tissue mass — with two real imaging models side by side. The X-ray panel is a genuine Beer–Lambert projection: a simulated beam of a chosen kVp crosses every voxel on its way to the detector, and mAs controls dose and photon noise. The ultrasound panel is a genuine pulse-echo B-mode simulation: a pulse of a chosen probe frequency travels into the phantom and reflects at every acoustic-impedance boundary, attenuating with depth and frequency exactly as real tissue does. Manipulating the parameters and watching both images update shows, concretely, why X-ray and ultrasound are complementary — X-ray passes through air and lights up bone, while ultrasound is blocked by air and bone but can see straight through fluid, even brightening the tissue behind it, a real effect called posterior acoustic enhancement.