A new scenario for the formation of Liesegang patterns is proposed. The periodic precipitation pattern formation in a gel column is interpreted as a moving boundary problem. The existing time law, space law, and width law are revisited and reformulated on the basis of a moving boundary assumption and more meaningful explanations are given. All the new equations suggested were found to be in good agreement with experimental observations. (C) 2002 Elsevier Science B.V. All rights reserved.