This is a very designed puzzle game. The principle is to draw a line in one stroke, and the line must go through all the lattices, and the line cant cross the wall or overlap.
On this basis, many new elements have been added. The front gates increase the difficulty by increasing the length of lines or increasing the control space of walls. In addition to the latter gates, keys that can acquire the corresponding color are added to increase the difficulty through the doors of the corresponding color.
In fact, the way of thinking is to draw a stroke and not overlap the lines, only horizontal zigzag or vertical zigzag, and finally to enter the next space with horizontal or vertical to select the zigzag method.
Because there are different colours of keys and different colours of doors, we need to consider the location of the doors and the corresponding keys on the basis of the normal selection of routes, and consider the route modification to select the key first, which makes it more difficult to consider the sequence.
And the number of keys and doors is not necessarily fixed, so more experiments are needed. The color of the door needs to correspond to the same color of the key to open, a key can only open a door, no key door can be passed through.
In addition, due to the wall or the dead corner caused by the starting point, whether vertical or horizontal twists are only in the end of the entry must be the place.
The game level that needs brainpower is many, want to study slowly!