Double Diamond
Problem space (Discover fan -> Define waist) then solution space (Develop fan + prototype -> Deliver waist). Frame an ambiguous problem and take it to a buildable solution.
When you have a 'How Might We' question and want a rigorous problem framing plus a tested, buildable solution spec.
Phasen
Discover
Surface the real, lived pains broadly across personas and angles. No solutions yet. Anti-steering is strongest here.
Define
Cluster the breadth into ONE core problem and a sharp Point-of-View (who + needs what + surprising insight). Frame the next How-Might-We.
Develop
Generate multiple solution candidates from the POV and build at least one real, minimal prototype to test.
Deliver
Have personas actually USE the prototype(s), then converge to a buildable specification (must-haves, who-for, validated solves, open risks).