Prototype of stacks in SwiftUI. See it in action: https://youtu.be/g7ag_P3TYZg

Stacks.swift

import SwiftUI

// The following code was generated using GPT 4-o1 with modifications and follow ups.
// 
// Initial prompt:
//
// How would you code a view in swiftui where there are 3 views on top of each other 
// (think 3 squares) and when tapped, they transition into a full window view where they 
// are all presented in a grid? This is more or less similar to what macOS has in stacks
// on the dock

struct StackedSquaresView: View {
    @Namespace private var animationNamespace
    @State private var isExpanded = false
    @State private var slideFactor = 1.0

    let squares = [Color.red, Color.green, Color.blue]

    var body: some View {
        ZStack {
            if isExpanded {
                ExpandedSquaresView(squares: squares, isExpanded: $isExpanded, namespace: animationNamespace)
                    .edgesIgnoringSafeArea(.all)
            } else {
                ZStack {
                    ForEach(0..<squares.count, id: \.self) { index in
                        squares[index]
                            .frame(width: 100, height: 100)
                            .matchedGeometryEffect(id: index, in: animationNamespace)
                            .offset(y: CGFloat(index) * 10.0 * slideFactor)
                    }
                }
                .onTapGesture {
                    withAnimation(.spring(duration: 0.8)) {
                        isExpanded = true
                    }
                }
                .onHover { next in
                    withAnimation {
                        slideFactor = next ? -2.0 : 1.0
                    }
                }
            }
        }
    }
}

struct ExpandedSquaresView: View {
    let squares: [Color]
    @Binding var isExpanded: Bool
    var namespace: Namespace.ID

    let columns = [
        GridItem(.flexible()),
        GridItem(.flexible())
    ]

    var body: some View {
        ScrollView {
            LazyVGrid(columns: columns, spacing: 20) {
                ForEach(0..<squares.count, id: \.self) { index in
                    squares[index]
                        .frame(width: 150, height: 150)
                        .matchedGeometryEffect(id: index, in: namespace)
                }
            }
            .padding()
        }
        .background(Color.white.opacity(0.3))
        .onTapGesture {
            withAnimation(.spring(duration: 0.8)) {
                isExpanded = false
            }
        }
    }
}

#Preview {
    StackedSquaresView()
    #if os(macOS)
        .frame(width: 800, height: 800)
    #endif
}