Loop Kropki (443)

Draw a single closed loop that travels horizontally and vertically through all white cells. The loop cannot touch or cross itself. The dots in the grid provide information about the lengths of loop segments (in number of cells). If there is a white dot between a pair of loop segments, then the difference of the lengths of these segments is exactly one. If there is a black dot between a pair of loop segments, then the quotient of the lengths of these segments is exactly two. There can be either black or white dot between loop segments of lengths 1 and 2. Not all possible dots have been given, but all the given dots must be part of the loop.

Reference: WPC 2016 (65)