for i in range(len(self.bits) - 19):
k = (self.get_sym(i, rec=False), self.get_sym(i+5, rec=False),
self.get_sym(i+10, rec=False), self.get_sym(i+15, rec=False))
for i in range(len(self.bits) - 19):
k = (self.get_sym(i, rec=False), self.get_sym(i+5, rec=False),
self.get_sym(i+10, rec=False), self.get_sym(i+15, rec=False))