Answer
The answer is as follows. 
Katrielle and the Millionaires' Conspiracy walkthrough
Puzzle Location: Bank foyer (The pen on the right desk)
In this picture, a square is coloured in if it has lines drawn around it.
Can you make it so that four or more squares are coloured in?
If you touch a pencil, the pencil will disappear and a line will appear in its place.
The line is drawn in the direction the pencil was facing.
Select the pencils in order to draw the necessary lines.
You can also delete a line by touching it.
The pencils disappear once they have been used.
The lines can only be used along one section, so be sure to use them wisely.
Colour in the square in the top-right corner.
Find a place where three squares can be enclosed at the same time.
Draw a line around three squares at the same time, excluding the square in the top-left corner.
The answer is as follows.