It's important that the error be additive rather than multiplicative, otherwise the area grows asymmetrically along a line.
Hopefully freehand drawings will work more intuitively now.
WPW3AVFS3WQVHNSCYVKX7ABWTQUUGVO4SXYCJZT2WOL6TOITX7EQC
B4YZWV6SQI6HK4PZAUKB5L6TISNECL72GFZZET34Q673OVN7IBRAC
LAW2O3NWVFTPBSKIMIXPAGYBDOCHYJNKCAVWKNKH62G42DIKZCYQC
K2X6G75Z6XBC4DVIRWC5HC7XA3A2SKOM3MWSQTCFEYWIJL7LME2QC
VHQCNMARPMNBSIUFLJG7HVK4QGDNPCGNVFLHS3I4IGNVSV5MRLYQC
XNFTJHC4QSHNSIWNN7K6QZEZ37GTQYKHS4EPNSVPQCUSWREROGIQC
BLWAYPKV3MLDZ4ALXLUJ25AIR6PCIL4RFYNRYLB26GFVC2KQBYBAC
DRFE3B3ZKRG4RY2R5Q3SDFD3LH4EXUX3CZCDFBNAXVI2SLDS57PAC