Mathematical tools
These features include are
1) Mathematical tools, such as compass, ruler and protractor with metric units
2) The ability to insert a table or a grid to show a line graph or any other type of graph
3) More types of clean lines, such as straight dotted lines, arrow lines, both of them together

Juan Alejandro Ramirez Calderon commented
Very important!!

Paulo H. Rozanez commented
Esse aplicativo é muito utilizado por estudantes de todo o mundo, por favor implante essas medidas.

VASS SAH commented
Very very important for mathematics bias. We plead with the developer to add these features.
Thank you 
danmaor8 commented
Yes please. As a computer science these math features are must and Squid app lacks of that.

Abby Lupi commented
As a physics student, this is ESSENTIAL for tablet based note taking

José Nelson Bastos Barbosa commented
Need to improve the shapes tool. It's very important for mathematicians.