Today, while visiting a client's apartment.
Came across a HDB mansionette (Executive Flat) that had it's main entrance door tilted.
On further observations; actually, it is far better not to tilt the main door. As originally, the main entrance faces an "opening".
After this person had tilted their main door; the main door faces the column wall. This results as a sha qi or poison arrow.
Please see photos...

These are more photos of this same unit main entrance door...
The strange thing is that if the main door WAS not tilted; the owner NEED not place a conVEX mirror above their main entrance door.
Here, the owner tilted the main door that now faces the column.....

Quote

On 10/6/2011 8:19:04 PM, Anonymous wrote:
Today, while visiting a
client's apartment. Came
across a HDB mansionette
(Executive Flat) that had it's
main entrance door tilted.On
further observations;
actually, it is far better not
to tilt the main door. As
originally, the main entrance
faces an "opening".After this
person had tilted their main
door; the main door faces the
column wall. This results as a
sha qi or poison arrow. Please
see photos...

Unit marked in RED "A" faces a very long corridor.
One plus point about the plants along marking in red "B" is that these plants help to slow down the sha qi towards Unit "A".
Please see photo...

Quote

On 10/6/2011 8:28:11 PM, Anonymous wrote:
These are more photos of this same unit
main entrance door...The strange thing
is that if the main door WAS not tilted;
the owner NEED not place a conVEX mirror
above their main entrance door.Here, the
owner tilted the main door that now
faces the column.....On 10/6/2011
8:19:04 PM, Cecil Lee wrote:
Today,
while visiting a
client's apartment.
Came
across a HDB mansionette
(Executive Flat) that had it's
main entrance door tilted.On
further observations;
actually,
it is far better not
to tilt the
main door. As
originally, the main
entrance
faces an "opening".After
this
person had tilted their main
door; the main door faces the
column wall. This results as a
sha qi or poison arrow. Please
see photos...

Another tilting gone wrong..

The Feng Shui Master tilted main door facing the rubbish bin. Hidden behind a door...

I understand the couple moved in in 2016. 

Today, it seems only the female party lives, here. Her partner had left. 

The rubbish bin is hidden behind the door to the right of this photo:-

A clear photo the the door.. to the right of this photo:-

[Below] Why your main door was tilted to face me? Beats me ?