shab sa2al Albert Einstein, el3alem elalamany el3azeem, "eh ser elnagah?" el3alem 2alo en ser elnagah howa elsho8l elgamed. ba3d kam yom elshab sa2al nafs elso2al tany. Einstein et3aseb gamed. maradsh ye2ool 7aga, bas katab kam kelma 3ala wara2a. 3aleha kan maktoob "A=X+Y+Z".
"ya3ny eh da?" sa2al elshab.
"A ma3naha nagah," sharah el3alem el3agoz, "X heya elsho8l elgamed, Y heya eltare2a elkwaysa w Z ma3naha batal rغy w enzil esht8al."
"Y" ma3naha   _  .
elsho8l elgamed el2owa elkbera elnagah el3azeem eltare2a elkwaysa