Adsense Use - Page Limits

[crabfoot]

Brethren,
My head is on upside down today. Forgive me, please ... I think some blood has entered my circulation and gone to my head.

My addled memory says that I can have a maximum of four Adsense units per site page, but that one of them has to be vertical.

I cannot find any verification of where I got this idea. Am I right, or should that be three units, and one has to be vertical?

Please help - I've tried looking at the back of the page, it says nothing.
At least the back of a whisky bottle tells you how many units are in it ...

 

[DomainPortfolio.ukDomainPortfolio.uk is verified member.]

From the Adsense help pages:

https://www.google.com/adsense/support/bin/topic.py?hl=en&topic=16760

How many Google ads can I display per page?

Currently, AdSense publishers may place up to three AdSense for content units on one webpage. You may also place a maximum of three link units and two search boxes on each webpage.

If you place more than on ad unit on a page, our system will display unique ads to each ad unit. Because the system automatically displays an optimal number of highly targeted Google ads on each page, in some cases, the maximum number of ads may not always appear. In this case, the ad unit will show as a transparent box, or will contain any alternate ad or color specified in the ad code.

 

[crabfoot]

Sincere thanks, Systreg - although you have effectively demonstrated that I am addled.

Unfortunately the system will not let me add to your reputation just now, because I did it before.

It does make me wonder just how "far gone" I am ...