'Look for the top-right corner of the cell, and make note of all column
boundaries (\'+\').'

def scan_right(self, top, left):

    colseps = {}
    line = self.block[top]
    for i in range((left + 1), (self.right + 1)):
        if (line[i] == '+'):
            colseps[i] = [top]
            result = self.scan_down(top, left, i)
            if result:
                (bottom, rowseps, newcolseps) = result
                update_dict_of_lists(colseps, newcolseps)
                return (bottom, i, rowseps, colseps)
        elif (line[i] != '-'):
            return None
    return None
