This private cul-de-sac at the end of 24th Avenue NE south of NE 60th Street appears, according to an article in the June 19, 1927, edition of the Seattle Post-Intelligencer, to have been established that very year. According to James Bush writing for the Seattle Sun, Ravenna Park (or perhaps a portion thereof) was once known as Twin Maple Park, and
[William Wirt] Beck is officially remembered by two of the smallest civic gestures ever performed. In keeping with the early practice of giving names to small bits of park property, the concrete-covered triangle of land at the intersection of 15th Avenue Northeast and Cowen Place was dubbed Beck Place. And, his beloved Twin Maples Park is memorialized by Twin Maples Lane Northeast, a half-block street where 24th Avenue Northeast meets the park border.
Note that the typos are in the Sun article, not this post — the sign quite clearly says Maple, not Maples.