material elastic [
	 name = steel
	 rho = 7800   # density
	 E   = 2.1e11 # young's modulus
	 nu  = 0.3    # poisson's ratio
]

material elastic [
	 name = copper
	 rho = 8940   # density
	 E   = 125e9  # young's modulus
	 nu  = 0.34   # poisson's ratio
]