US Patent 11536307 Symmetric tongue and t-cross

A set including a first panel, a second panel and a mechanical locking device for locking the first panel to the second panel, the mechanical locking device includes an insertion groove at the second edge surface, a flexible tongue positioned in the insertion groove and an edge tongue including a tongue groove, the flexible tongue includes a first locking surface and a second locking surface, the first locking surface is configured to cooperate with the tongue groove for locking of the first panel to the second panel in a first direction when the flexible tongue is positioned in the insertion groove in a first orientation, the second locking surface of the flexible tongue is configured to cooperate with the tongue groove for a locking of the first panel to the second panel in a first direction when the flexible tongue is positioned in the insertion groove in a second orientation.