We started coming up with natural explanations. The pulsating light could come from a laptop on standby (you know sometimes they have a small lamp blinking), but there were no laptops near.. It could also be the light reflecting from a watch (there of the round shape), but again, no watches near..
We decided that it must be a light coming from the livingroom because you can see that the pattern is shaded on the right side because of the wardrobe door. The scary thing is that we only have windows on the wall the pattern came on, and the sun in the livingroom (the room next to the bedroom) comes through the windows at 1-2 in the afternoon and this was in the morning.
The explanation we came up with is the following:
The sun must have shone on something in the harbour outside our livingroom window. That thing were probably moving (which of the pulsating) and giving a reflex on our electricity meter in the livingroom outside the bedroom. Lastly the meter must have passed the light on to the bedroom wall. Logic huh!? (please say it's logical!). We thought of trying it out by shining a flashlight on the meter, but decided not to. What if it didn't come any relfections?! We just accepted the electricity-meter-explanation:
Do you have any idea of what it could have been??