non slip mahjong matSilicon‑valley‑multicultural‑tech‑employee‑social‑groups‑based‑inside‑San‑José‑regularly‑hold‑after‑work‑mahjong‑game‑nights‑to‑help‑busy‑office‑workers‑relax‑and‑build‑friendly‑inter‑colleague‑social‑relationships‑outside‑formal‑work‑environment‑settings.