The All Leads
The diagram shows all the views from the limb leads (I,II,III) and the augmented leads (aVR, aVL, aVF).
On a standard ECG printout the information from the limb leads and augmented leads is presented on the left half of the paper and the information from the chest leads (V1-6) is presented on the right half of the paper.
Down at the bottom, spanning the entire width of the printout there is an extended run of one of the leads. Most of the time this is limb lead II. It is called the rhythm strip and is used to calculate the heart rate.