          | &quot;A&quot;           |
| &quot;A&quot;           | &quot;i&quot;           |
| &quot;i&quot;           | &quot;A&quot;           |
| &quot;i&quot;           | &quot;i&quot;           |
o---------------o---------------o
| &quot;B&quot;           | &quot;B&quot;           |
| &quot;B&quot;           | &quot;u&quot;           |
| &quot;u&quot;           | &quot;B&quot;           |
| &quot;u&quot;           | &quot;u&quot;           |
o---------------o---------------o

Taking the 2-adic projectio