1967. What characters can be added here so that each character contains a part of the previous character?

a) 炎 -> 炉 -> 所 -> 近  

炎  EN, honou - flame

炉  RO - furnace, hearth

所  SHO, tokoro - place

近  KIN, chika(i) - close, near

b) 案 -> 林 -> 相 -> 睡  

案  AN - plan, proposal

林  RIN, hayashi - woods

相  SOU, SHOU, ai - aspect, minister, partner

睡  SUI - sleep