diff --git a/list/list.go b/list/list.go
index 2a62437..04e6163 100644
--- a/list/list.go
+++ b/list/list.go
@@ -5,12 +5,20 @@ import (
 	"strings"
 )
 
-type IList interface {
+type ICollection interface {
 	Conj(data any) IList
+	IsEmpty() bool
+}
+
+type ISeq interface {
 	First() any
 	Rest() IList
+}
+
+type IList interface {
+	ISeq
+	ICollection
 	String() string
-	IsEmpty() bool
 	Len() int
 }
 
@@ -42,22 +50,7 @@ func (this *List) Conj(val any) IList {
 }
 
 func (this *EmptyList) Conj(val any) IList {
-	return Conj(nil, val)
-}
-
-func Conj(this IList, val any) IList {
-	if this == nil {
-		return New(val)
-	} else {
-		return this.Conj(val)
-	}
-}
-
-func Rest(this IList) IList {
-	if this == nil {
-		return emptyList
-	}
-	return this.Rest()
+	return New(val)
 }
 
 func (this *List) Rest() IList {
@@ -71,17 +64,13 @@ func (this *EmptyList) Rest() IList {
 	return emptyList
 }
 
-func First(this *List) any {
+func (this *List) First() any {
 	if this == nil {
 		return nil
 	}
 	return this.Value
 }
 
-func (this *List) First() any {
-	return First(this)
-}
-
 func (this *EmptyList) First() any {
 	return nil
 }
@@ -98,7 +87,7 @@ func (this *EmptyList) IsEmpty() bool {
 	return true
 }
 
-func String(this *List) string {
+func (this *List) String() string {
 	if IsEmpty(this) {
 		return "()"
 	}
@@ -107,17 +96,13 @@ func String(this *List) string {
 	sb.WriteRune('(')
 	// Iterate and print elements
 	var e IList
-	for e = this; !IsEmpty(e); e = Rest(e) {
+	for e = this; !IsEmpty(e); e = e.Rest() {
 		sb.WriteString(fmt.Sprint(e.First()))
 		sb.WriteRune(' ')
 	}
 	return sb.String()[:sb.Len()-1] + ")"
 }
 
-func (this *List) String() string {
-	return String(this)
-}
-
 func (this *EmptyList) String() string {
 	return "()"
 }
diff --git a/list/list_test.go b/list/list_test.go
index 61aa514..017fdae 100644
--- a/list/list_test.go
+++ b/list/list_test.go
@@ -37,7 +37,7 @@ func TestListRest(t *testing.T) {
 	assert.Equal(t, "(5)", l.Rest().Rest().String(), "should return rest sublist")
 	assert.Equal(t, "()", l.Rest().Rest().Rest().String(), "should return rest sublist")
 	assert.Equal(t, Empty(), Empty().Rest(), "should return rest sublist")
-	assert.Equal(t, Empty(), Rest(Empty().Rest()), "should return rest sublist")
+	assert.Equal(t, Empty(), Empty().Rest().Rest(), "should return rest sublist")
 }
 
 // generative tests
diff --git a/vector/vector.go b/vector/vector.go
index f20727a..360353c 100644
--- a/vector/vector.go
+++ b/vector/vector.go
@@ -21,7 +21,7 @@ func (this *Vector) Init() *Vector {
 	return this
 }
 
-func Conj(this *Vector, data any) *Vector {
+func (this *Vector) Conj(data any) *Vector {
 	newVec := New()
 	for _, el := range this._slice {
 		newVec._slice = append(newVec._slice, el)
@@ -30,10 +30,6 @@ func Conj(this *Vector, data any) *Vector {
 	return newVec
 }
 
-func (this *Vector) Conj(data any) *Vector {
-	return Conj(this, data)
-}
-
 func String(this *Vector) string {
 	if this == nil {
 		return "[]"
@@ -54,7 +50,7 @@ func (this *Vector) String() string {
 func ToList(this *Vector) list.IList {
 	l := list.Empty()
 	for i := len(this._slice) - 1; i >= 0; i-- {
-		l = list.Conj(l, this._slice[i])
+		l = l.Conj(this._slice[i])
 	}
 	return l
 }