If I have a *custom type* like for ex. a `Range`: Public Class Range Sub New(minimum As Single, maximum As Single) Me.Minimum = minimum Me.Maximum = maximum End Sub Public Property Minimum As Single Public Property Maximum As Single Public ReadOnly Property Delta As Single Get Return Maximum - Minimum End Get End Property End Class '----------- 'Some methods... This type should be used in the domain model(implementing DDD), in the business logic when doing stuff and also in the data layer, where it will be stored as a complex type. So : - should I define such classes in a Project `App.Common` and reference this assembly everywhere (*my choice for now, but don't know if having references in domain model project is an anti-pattern?*) - should I define it in my domain model and reference my domain model everywhere where it is needed. (*maybe better? since Domain model is core in DDD, but the type is not a domain or value object...*) - should I create different classes for each layer (*which don't make sense to me, since I want to handle it like another type and not as Object*)?