This is a diagram demonstrating an example of multi-tier architecture. From the left, there are three rounded boxes, placed vertically above one another. They all have the same text inside: client (browser). Below these, there is a rectangle, with text that reads client tier. There are three arrows coming from the right, pointing towards the three rounded boxes. From this, the line goes into one and comes from a cloud shape. Below the cloud, there is a rectangle with the text: internet. Pointing to the right, there is an arrow coming out of the cloud and pointing towards a rounded box, with the text inside: web server. There is a rectangular box below it, with the text: server tier. On the right side of the rounded box, there is a double ended arrow pointing to the current rounded box and another rounded box on the right. The rounded box on the right of this has the text: business logic and a rectangular box below it, with the text: middle tier. To the right of the rounded box there is a double ended arrow, going to another set of arrows which point towards two further rounded boxes. The first one, at the top, has the text: sales records database, and the second one, below it, has the text: stock level database. Below this is a rectangular box that has the text: data tier.