Can cellos play double stops?
If you have a big hand, or are very flexible, then you can play the cello more like a violin …… and you can put the double-stops back in! ... And even the minor third hand frame can block and rigidify the hand, making vibrato difficult.
Can a cello play thirds?
In the lower register of the cello, most players use 4 –1 for every 3rd; they only finger the 3rds using the thumb higher up the fingerboard. The thumb is stronger than the fingers and can also be used to great effect in the lower positions.