You are writing an analysis program that identifies textures in black$-$and$-$white images. One subroutine in this program is supposed to detect whether an entire row of pixels is covered by a pattern of regularly$-$spaced black pixels. That is$,$ it determines if every pair of adjacent black pixels is separated by the same number of white pixels.

Write a program that simulates this subroutine using a textual input representation. Each row of image pixels is represented by a single line of text. Each asterisk $(*)$ represents a black pixel, while each period $(.)$ represents a white pixel.