Click empty space → add element
Drag from dot to dot → toggle R⟨x,y⟩
Shift+Drag → toggle R⟨y,x⟩
Click arrow → delete arrow
Select node + Delete/⌫ → delete node
Select node + L → toggle loop R⟨x,x⟩
Sentence
Use only the binary relation symbol R with the usual connectives/quantifiers. ASCII like ->, ~, /\, \/, or the words “and/or/not/forall/exists” are fine.