par(mfrow = c(2,2))   # 2×2 layout

plot(returns$Silver, returns$HZL,
     xlab = "Silver Returns", ylab = "HZL Returns",
     main = "Silver vs HZL", pch = 16)
abline(lm(returns$HZL ~ returns$Silver), col = "red")

plot(returns$Silver, returns$Vedanta,
     xlab = "Silver Returns", ylab = "Vedanta Returns",
     main = "Silver vs Vedanta", pch = 16)
abline(lm(returns$Vedanta ~ returns$Silver), col = "red")

plot(returns$Silver, returns$HCL,
     xlab = "Silver Returns", ylab = "HCL Returns",
     main = "Silver vs HCL", pch = 16)
abline(lm(returns$HCL ~ returns$Silver), col = "red")

plot(returns$Silver, returns$NMDC,
     xlab = "Silver Returns", ylab = "NMDC Returns",
     main = "Silver vs NMDC", pch = 16)
abline(lm(returns$NMDC ~ returns$Silver), col = "red")

par(mfrow = c(1,1))   # reset layout