A black hole drawn live by tracing the path of light for every pixel. Drag to move around it.
The event horizon is the surface nothing returns from. The shadow you see is about 2.6 times wider, because light passing that close gets pulled in too. Switch off Bend light to see the horizon at its true size.
The disc is flat, like Saturn's rings. Light from the part behind the hole bends up and over it to reach you, and more bends underneath. You see the far side lifted above the shadow and its underside tucked below.
That light skimmed the hole at about 1.5 times the horizon's radius and went part or all of the way around before escaping. Each extra lap makes a thinner, fainter ring.
Gas at the inner edge orbits at about half the speed of light. The side rushing toward you looks brighter and bluer, the side moving away dimmer and redder. Switch off Doppler boost to compare.
What is real and what is not: this is a non-spinning (Schwarzschild) black hole, and the light paths follow its actual equation of motion, stepped a few hundred times per pixel on your graphics card. Distances are in Schwarzschild radii, the radius of the event horizon. The disc starts at 3 radii, the closest stable orbit. Its colours and texture are chosen to be visible to the eye. A real disc this close to a black hole shines mostly in X-rays.