Två biljardgeometrier har studerats, där båda är deformationer av en cirkel. Den ena är ellipsbiljarden och är med för jämförelse och den andra är Robnikbiljarden som bra belyser Biljardproblemens dynamik. Här centraliseras undersökningen till de periodiska banornas stabilitet..

Objective: In recent years there has been an increasing interest within the clinical (medical) science in measuring people?s health. When estimating quality of life, present practise is to use the EQ-5D questionnaire and an index which weighs the different questions. The question is what happens if the individuals estimate there own health, would it differ from the public preferences? The aim is to make a new prediction model based on the opinion of patients and compare it to the present model based on public preferences.Method: A sample of 362 patients with unstable coronary artery disease from the Frisc II trial, valued their quality of life in the acute phase and after 3, 6 and 12 months.