In the Foundations stage, Time, Cost and Quality are fixed and the requirements prioritised meaning you will always get a viable solution, on time and on budget, if the correct practices of prioritisation and timeboxing are adhered to.
Once the project moves out of the Foundation stage, we can start building /creating your vision.
We do this in small pieces, called increments. Each increment is planned and timeboxed. After each timebox is completed, the solution has been evaluated and signed off, at the end of each increment.
Everything is tested and signed off by you, the customer. This means you know what is being completed and you are happy with the quality.