100.—On the Ramsgate Sands.
Reading edition
100.—On the Ramsgate Sands.
Just six different rings may be formed without breaking the conditions. Here is one way of effecting the arrangements.
ABCDEFGHIJKLM
ACEGIKMBDFHJL
ADGJMCFILBEHK
AEIMDHLCGKBFJ
AFKCHMEJBGLDI
AGMFLEKDJCIBH
Join the ends and you have the six rings.
Lucas devised a simple mechanical method for obtaining the n rings that may be formed under the conditions by 2n+1 children.