def blend(arr1, arr2, alpha=0.5):
	"""Blend 2 arrays together, mixing with alpha.

	Parameters
	----------
	arr1:array
		Image 1.
	arr2:array
		Image 2.
	alpha:float
		Higher alpha makes image more like image 1.

	Returns
	-------
	array
		Resulting image.

	"""
	return alpha*arr1 + (1.-alpha)*arr2