An article (14; 36; 60; 120) comprising a structure formed of a plurality of fused foam particles, wherein: each individual foam particle of the plurality of fused foam particles includes a first surface formed of a first thermoplastic elastomer material, and the first surface also includes one or more fused regions affixing the individual foam particle to a second surface of one or more adjacent foam particles, the second surface of the one or more adjacent foam particles comprises a second thermoplastic elastomer material; the fused regions include a portion of the first thermoplastic elastomer material from the first surface of the individual foam particle intermingled with a portion of the second thermoplastic elastomer material from the second surface of the one or more adjacent foam particles; the structure formed of the plurality of fused foam particles includes a plurality of gaps between particles, with the gaps occupying at least 10 percent of a total volume of the structure; and prior to fusing, at least 20 percent of the plurality of foam particles are spheroid or ellipsoid in shape and have a number average particle size of 0.04 millimeters to 10 millimeters in a longest dimension, and at least 20 percent of the spheroid or ellipsoid foam particles in the structure retain a substantially spheroid or ellipsoid shape; wherein the article is characterized by a plurality of sub-regions (121a, 121b, 121c, 122, 123; 124a, 124b, 124c) comprising differentially fused foam particles, the sub-regions comprising a first sub-region (121a, 121b, 121c; 124a) characterized by a first property and a second sub-region (122; 124b) characterized by a second property, wherein the first property is not equal to the second property, and wherein the first property and the second property are flexural modulus, stiffness, bulk density, or resilience. each individual foam particle of the plurality of fused foam particles includes a first surface formed of a first thermoplastic elastomer material, and the first surface also includes one or more fused regions affixing the individual foam particle to a second surface of one or more adjacent foam particles, the second surface of the one or more adjacent foam particles comprises a second thermoplastic elastomer material; the fused regions include a portion of the first thermoplastic elastomer material from the first surface of the individual foam particle intermingled with a portion of the second thermoplastic elastomer material from the second surface of the one or more adjacent foam particles; the structure formed of the plurality of fused foam particles includes a plurality of gaps between particles, with the gaps occupying at least 10 percent of a total volume of the structure; and prior to fusing, at least 20 percent of the plurality of foam particles are spheroid or ellipsoid in shape and have a number average particle size of 0.04 millimeters to 10 millimeters in a longest dimension, and at least 20 percent of the spheroid or ellipsoid foam particles in the structure retain a substantially spheroid or ellipsoid shape; wherein the article is characterized by a plurality of sub-regions (121a, 121b, 121c, 122, 123; 124a, 124b, 124c) comprising differentially fused foam particles, the sub-regions comprising a first sub-region (121a, 121b, 121c; 124a) characterized by a first property and a second sub-region (122; 124b) characterized by a second property, wherein the first property is not equal to the second property, and wherein the first property and the second property are flexural modulus, stiffness, bulk density, or resilience.