Bruce Nauman 

Julie Head/Julie, Head, Upside Down, Tongue to Tongue, 1990

Right part: 10 5/8 x 8 7/8 x 5 1/2 inches (27 x 22.5 x 14 cm) 
Left part: 9 7/8 x 8 5/8 x 5 3/4 inches (25.2 x 22 x 14.7 cm) 
Overall: 11 x 18 x 7 inches (27.9 x 45.7 x 17.8 cm)