x1 is a torus of genus x2 (li; nonnegative integer), having x3 (li; nonnegative integer) distinct cusps, and with other properties/characteristics x4, by standard/in sense x5; x1 is an x2-fold torus.
The contextless default for x3 is probably 0. A coffee mug is a 1-fold torus by the standard of topology but not by the standard of geometry. x2 can be only a nonnegative integer or some sort of infinity. See also: cukydjine, where the material properties and realization of the (physical) object matter. x2 = 0, x3 = 1 means that x1 is a horn(ed) torus (the cross-section with the two circles has them intersecting at exactly 1 point); x0 = 1, x3 = 2 means that x1 is a spindle torus (the cross-section with the two circles has them intersecting at exactly 2 points); x2 = 0, x3 = ro means that x1 is a sphere (the cross-section with the two circles has them intersecting at all of their points (which also is uncountably infinitely many) so that they are mutually indistinguishable); x2 = 1, x3 = 0 means that x1 is a standard/basic torus (the cross-section with the two circles has them intersecting at exactly 0 points; the result is a classic 'donut' shape).