# \u and up to 4 hex digits
ruble <- "\u20BD" # ₽
lambda <- "\u03BB" # λ
# Braces mark where the digits end
lambda_braces <- "\u{03BB}" # λ
# \U and up to 8 hex digits: beyond 4 digits
smile <- "\U0001F600" # grinning face
cat("ruble =", ruble, "\n")
cat("lambda =", lambda, "\n")
cat("lambda_braces =", lambda_braces, "\n")
cat("smile =", smile, "\n")