What kind of curvature characterizes a closed universe where gravity curves space back on itself?

Positive curvature (Sphere-like)

A closed universe is defined by having positive curvature. This geometric property is analogous to the surface of a sphere, meaning that the influence of mass and energy creates enough gravitational pull to curve space inward upon itself. If a universe possesses positive curvature, its total volume must be finite. This finiteness implies that if an observer were to travel in a straight line indefinitely, they would eventually traverse the entire expanse and return to their original starting position, much like traveling around the Earth's surface. This condition is mathematically linked to a density parameter $\Omega$ being greater than 1, indicating that the density of matter and energy exceeds the critical density required for flatness.