half00halfs00halfssxshalfxlastbit00lastbits0s0lastbitssxlastbitxconv0consnil0convsxconsconvhalfsxlastbitsxhalfssxhalfxlastbitssxlastbitxconvsxconvhalfsxconvsxhalfsxconvsxlastbitsxtrueconvsxconvhalfsxtrue12341conv1221half1-111s1111000halfs00halfssxshalfxhalf00convsxhalfsxfalse2halfssxhalfxtrue21half111s1111convsxlastbitsxfalselastbitssxlastbitxtrue1lastbit111s1111