ContentView.swift

struct ContentView: View {
  @StateObject var viewModel = ViewModel()
  @Namespace var colorSelectionNamespace
    
  var body: some View {
    VStack {
      HStack {
        ForEach(viewModel.topColors) { item in
          Button(action: { viewModel.selectTopColor(item) }) {
            Rectangle()
              .foregroundColor(item.color)
              .frame(width: 40, height: 40)
          }
          .matchedGeometryEffect(id: item.id, in: colorSelectionNamespace)
        }
      }
      .frame(minHeight: 50)
      Spacer()
        .frame(height: 200)
      HStack {
        ForEach(viewModel.bottomColors) { item in
          Button(action: { viewModel.selectBottomColor(item) }) {
            Circle()
              .foregroundColor(item.color)
              .frame(width: 20, height: 20)
          }
          .matchedGeometryEffect(id: item.id, in: colorSelectionNamespace)
        }
      }
      .frame(minHeight: 50)
    }
  }
}