Which techniques does the author use to present the relationship between Mickey and Linda in 'Blood Brothers'?

In Blood Brothers we see Mickey and Linda grow from young children to teenagers and to adults with the clever technique of using the same actors throughout so that they must play Mickey as a 6 year old, and then later as a grown man. The playwright cleverly uses humour in the scenes when they are very young and this means that we as an audience become invested in them. As their relationship deepens and becomes more troubled we feel their emotions more keenly because of our earlier investment in their characters. The contrasts between Mickey and Linda and Eddie also help the audience to understand the different relationships. Contrast and conflict is so key in drama, and Blood Brothers uses it very effectively.