The deCordova Biennial’s showstopper: Hamra Abbas’s riveting “Kaaba Pictures” series.

Archival pigment prints of photographs, Abbas’s series looks like paintings — cartoony geometries with architectural and ornamental flourishes.

The series depicts the Kaaba, the black granite cube of a building, destination point of the pilgrimage to Mecca, said to be built by the Prophet Abraham.

Lynne Harlow’s “So I Built a Raft,” an enclosed curtain of Day-Glo green ribbons that riffle on the breeze and glow beneath magenta lights.

Other strong pieces don’t rely on color. Jilaine Jones’s “Wonder World,” a fleet and airy concrete and steel abstract sculpture.