First of all I was looking at alkaline's website on introductions and so on. I was looking at lakes, when I noticed in 4-D that lakes can be globular, flat, and linear. I understand globular which is very thick, which needs a long distance cylindrical bridge to travel through it. I also understand a flat lake which is thin, which needs a short distance cylindrical bridge to travel through it. Now a linear lake I do not understand, it says for a linear lake no bridge is neccessary. However in the diagram, it shows the arrow, which would be a Tetronian, and it travels straight but when it reaches the lake it shows the arrow "hopping" over the lake and continuing, but a lake is not able to be jumped over. So wouldn't a short half-circle bridge be needed to cross the river-like lake? Because a 4-D linear lake would be like a 3-D linear lake or even a 3-D river, which needs a half-circle bridge to cross or just a straight bridge, however in 4-D a straight bridge wouldn't be possible because you'd walk straight into the river which wouldn't be confined to the ground.
Well if needed, here is a link to the page on bodies of water I was looking at: http://www.tetraspace.alkaline.org/page8.htm