operater stack | operand stack | current operands
|(f,&(t,t)) |
↑
|(f,&(t,t)) (f)
↑
|(f,&(t,t)) |,& (f)
↑
|(f,&(t,t)) |,& (f) (t)
↑
|(f,&(t,t)) |,& (f) (t,t)
↑
|(f,&(t,t)) | (f,t)
↑
|(f,&(t,t))
↑