I am going to start by introducing the bijection between two-row (resp. three-row) rectangular standard Young tableaux and non-crossing matchings (resp. sl_3 webs) and the bijection between promotion of tableaux and rotation of webs. Last year, sl_4 webs were finally defined from hourglass plabic graphs. However, their construction involves approximately 100 growth rules. In this talk, I am going to introduce a conjecture on a novel way to construct such webs by "stacking" sl_3 webs.