User blog:Googleaarex/Dollar Function vs EUAN

a$b = a+b

a$[0] = a*2

a$[0][0] = a*2^2

a$[1] = a*2^a ~ a^a has arrow-level \(\uparrow\)

a$[1][1] ~ (a^a)^(a^a) = a^a^{a+1}

a$[2] has arrow-level \(\uparrow\uparrow\)