carbocation rearrangements can also occur by the shift of an alkyl group with its electron pair.
for example, reacion of 3,3-dimethyl-1-butene with HCI leads to an equal mixture of unrearranged 2-chloro-3,3-dimethylbtane and rearranged 2-chloro-2,3-dimethylbutane.
in this instance, a secondary cabocation rearranges to a more stable teriary carbocation by the shift of a methyl group: